Gamespy is used in the multiplayer part of certain games - mostly the games where the developers are mad at Valve software about something. Like gearbox used gamespy for the multiplayer in Boderlands, gamespy is used in Unreal Black Edition for multiplayer,,,,,.
Besides logging into gamespy to play those in multiplayer, no I do not use gamespy for anything else.
Back in the late 1990s I used gamespy a lot - and Quakespy before it was Gamespy.
But these days, I just use Steam.