I have a few games that has this weird feature that enables you to holster your weapon and just walk around.
Why is it there? What purpose does it have? For screenshot capturing? Seems like a long stretch to me.

Depends on the game, really. There's a mechanic that I've seen for the first time in Thief and had been used in many games since where holstering weapons makes you less visible when you're trying to be stealthy. Then in some games, when they require NPC interactions, holstering a weapon can make NPC reaction towards you less hostile. In some games, you may get to run faster with a holstered weapon. And then, of course, there are those in which the feature is completely pointless - but it's also quite easy to implement, so why the hell not.

Some games if you approach someone without your gun/weapon holstered they don't take kindly to it. I agree that it's kind of silly for games where it doesn't matter, but I love it in other titles where it actually plays a part in your interaction with NPCs.

Ninjad by an evil computer program wearing a monocle. How sad. :P

don't get it . deus ex, tekwar, and several first-person games have that.

Stalker is the only game I know of that does this correct.

Yep it really is a silly feature most of the time shoved in for seemingly no reason.

Now thinking about it, I do tend to holster weapon if there's a lot of exploration in the game, for a few reasons:
a) So I don't accidentally shoot and wate ammo
b) Because the gun takes up screen space and I have better chance of noticing stuff with it holstered

I think it's Elder Scrolls where that has really evolved. In Morrowind they don't care, but just one game later in Oblivion they get really pissed if you are holding a weapon.

I do like that in Skyrim, mere act of holstering a weapon causes your opponent to do the same when his disposition is high enough.

In Deus Ex, it makes sense, because that's an RPG, not really a shooter. Guns are generally treated like any other inventory item in that game.

At the beginning of Doom 3 they get pissed too if you have your gun out.

This thread is just dying for some really dirty double entendres. :P

Even Gothic 1 (released in early 2001 so even before Morrowind) had it that if you ran into a camp or town with a drawn weapon the NPC's would draw their weapons and warn you to put it away. If you comply, they put away theirs too and everything is fine. If you don't comply, they attack you and usually alarm the guards too.

Actually they freak out if you fire it at someone or just in the air. I shot everyone anyway. :P

THAT'S RIGHT! :P Now I remember! "Don't discharge that weapon in here marine!"