All team and enemy gun sounds are the same for competitive integrity. So you always know what gun the enemy has if you hear it. Same goes for, most, animations.
So this only affects you if you grab a gun from the floor and while spectating. I can see how it could be useful for some people that get really distracted from a skin they never asked for in a serious competitive game and so, I do agree that the existence of such option will be appreciated by some.
In the other hand, it might be considered as an additional way of marketing by Riot so they may never do it. Like "Oh I just picked up a cool gun skin from the ground and now i kinda wanna buy it" you know.