JakobFel: The community wishlist is massive because anyone can add a game they'd like to see on GOG. If you're wondering why you should buy on GOG, I'd recommend checking the
About page. In short, GOG offers games DRM-free (meaning you can access the installation files without restrictive digital rights management software), there's an optional game client that you CAN use but don't have to (unlike most sites), they offer a 30-day no-questions-asked refund policy, most games come with additional goodies (manuals, maps, soundtracks, interviews with the developers, that sort of thing), old games tend to work better from GOG and perhaps most importantly: every game you buy here, you own. With Steam and other platforms, you're really just renting the rights to play the game indefinitely but on GOG (and other DRM-free sites), you own what you buy.
yes these are the good sides, but it doesn't really matter to me, I came here for games.
Also, you said that there are almost no old games here but that's just not true. No other platform out there has as many old games and classics than GOG. That's one thing that even the critics of GOG have to admit.

wizzardyno: but here I would argue with you, there are very few exclusive old games here, for example, there are no old games from Rockstar (Max Payne, Manhunt, GTA...) that are on the Steam and many more old games like Duke Nukem 3D, Old Call of Duty Series, ets.
I understand that adding games from the wishlist community is not so easy, but why is it needed, there are many good old games, and people vote for them. But apparently this list is just for show, because they will never be added to the store.
Well, it depends on what you mean by "old". And in some of those cases, you can blame the publishers or whoever owns the copyright. GOG has quite a struggle with licensing games here sometimes because publishers want total control and kinda flip out when they find out that people actually own their games over here.
The truth is that no other platform has as many old games as GOG (even if your preferences aren't here yet) and they most definitely run the best over here because of how GOG works on them so they run better on modern OSes. Even so, buying from GOG has plenty of other benefits to justify shopping here, even if specific old games you're looking for aren't here yet. Add your vote to the wishlist entries you want, grab a few games and stick around, you might like it here!
available to check out if you want to try out the GOG experience before buying.