Hell yes. I'm not that much of a gamer, but I will start linking this into my mesa builds because I hate software patents. I will patiently wait for men in uncomfortable shoes to show up at my door because of this trivial infraction.
Someone will use the first, some other one the latter and they could diverge in the future. Ideally these tree should be removed and the lib put at: http://cgit.freedesktop.org/mesa/
rather than in some user specific directory.
Unreal Tournament (Linux version) uses it. Can't remember any other native games off the top of my head.
I think some games will use it under Wine. A few games like Black & White still need an extra patch that the Wine devs are not willing to merge. This patch only came about very recently. I've been waiting for it for years.