They're nowhere on the screen.
I've also tried to buy another game since, and no pop up or possibility to choose GOG credits :(

Did you buy another game after Witcher 3? Maybe it defaulted to spending your store credit, first?

Not normal. The store credits should be available as soon as the purchase is complete. I advise contacxting support

I bought a pack after but I had to pay full price with Paypal, since the credits were not available :x

You know those market stands in the near east where people who look like tourists get prices up to 5 times as high as the ones their townspeople get?

This is what is happening here and I'm always baffled how many people think it's ok.

Just to make sure it is not one of the common overseen problems. Did you buy Witcher 3 with euros or with dollar? And did you change your currency setting afterward? I am asking since the credit will only be there if you have the same currency as the one you had while getting the credit.

Considering GOG offers store credit for the purchase of regionally priced games how does this help their revenue stream in any way.

I simply don't understand why this is such a problem.

There were actually few downsides for GOG in what they were doing there. Assuming the games they're offering would not have been offered without regional pricing at least.

A) They get to sell games they otherwise wouldn't have
B) They pretty much break even on regions they do offer compensation, and make normal profit on the game in all the others, so in the end, it's a win
C) More games, is bigger catalog, more attention, so draws in more customers who may buy other games on their store.

Completely wrong.
We lost a whole lot of good games (Nordic and Frictional) because of the change and most of the now regionally priced titles we got afterwards would have been here anyway (as announced in the Kickstarters a long time ago for example).

We didn't get any AAA games as promised because DRM is the main problem there.

And how is any of this bad for the current customers? More games on GOG = more games DRM-free which is the main reason (and often the ONLY reason) most of us are here.

Look, I get that people outside the US may get a bit upset because they pay more. But truth is, there are reasons for that. I live in Europe and I get it but let's just try to get you all to understand why.

There's two main reasons for the higher price of games in Europe (and other countries, but I'm going to focus on europe). These are:
1 - Higher taxes. Taxes on games and other entertainment products are commonly higher in Europe. In my country for example it's 23%. In the US sales tax very rarely goes above 10% (it varies by jurisdiction).
2 - In Europe and most other countries, sales tax is included in the price. In the US (and Canada as far as I know) it isn't. So if you are in a store in Europe and the price tag says "€50", when you get to register you pay €50 and nothing more. In the US if the price tag says "50$", you don't pay 50$. You pay 50$ PLUS sales tax. If sales tax is 8% for example, you end up paying 50$+50*0.08= 54$. If it were 23% like it is where I live it would be 61.5$ even though the price tag said 50.

By giving back the difference GOG is also giving you back the tax difference, therefore they quite probably actually make less money from selling games in Europe.

This is not because of regional pricing per se. Nordic clarified:

"- Our own equal treatment principles remain coherent; we do not want to put one of our partners in a special place and cause a stir with other partners.
What do we mean with the last point exactly?
Given gog.com’s decision to aim for an exchange-rate orientated pricing would leave us in the unenviable position of constantly having to adapt our pricings in all territories on- and offline to ensure an equal treatment. As exchange rates are very dynamic in nature with the potential of shifting rapidly, and given our network of more than 100 off- and online partners, this will result in a significant amount of extra time and work. For a company of our size, this can result in a non-manageable effort and will heavily impact our work hours"
(http://www.gog.com/forum/general/last_chance_special/post729)

By what I read here allowing the publishers to set their own prices (like Steam does) would actually solve the problem. Nordic pulled out because of GOG trying to appease the vocal members of it's community.

Acutally the real reason for this is as the other smaller developer said when it pulled out of gog together with Nordic is that the people in other stores would be able to see when gog uses regional currency how much they are screwing them up in other stores (if the prices weren't regionally priced) and also since they have agreements with other stores they could not allow gog users smaller prices. So to say if gog uses different currencies the prices must be the same as in all other stores.

I know. It's why letting publishers set their own prices regionally would solve the problem. Which makes me wonder why they couldn't simply shift to regional pricing instead of pulling out altogether. Maybe that would require them to raise the price and they didn't want to do that?
It feels like the pricing structure and policies in GOG is simply too wonky and big shoot to the foot.

I paid with euros, and my account is set to France/euros since beginning.

But the problem is solved :)

No formal response from support at the moment, but they've solved something I guess, because my credits are now present as expected on my account page and I can select them to pay.

Thanks everyone for the help ;)

This really is nothing like the statement they made as far as I remember it. Their statement came down that they didn't want to deal with the price variancy GOG would have whenever they adjust their price and the hassle that would result from that because they have a ton of deals with other publishers and they'd need to be treated equally. Given they have 35? games that's no doubt a ton of work. (assuming the story holds up of course but this is how I remember their statement)

You were asking how it benefited GOG's revenue stream. That's what I answered.

You might want to add some points to reading skills - Matruchus is referring to Frictional Games, not Nordic.