I am definitely not working on any Hollywood level projects...but I need XLR all the time, its not just cable runs where it is important, it is also the wireless mics that I use, the wired taps into the mixing boards, concerts, wedding DJs, all use XLR; and yes, sometimes I do need a 50' wired run from a mixing board to my XLR input.
I caveat all of this with the fact that I do not know anything about USB audio, maybe it really is that great and camera makers should include it in their cameras, but I do know that I've had to connect to almost everything imaginable and I have spent a small fortune on prosumer grade audio gear and it is all based on the XLR interface.