2 guitarists with 2 amps each, multiple amps "waiting" while you switch scenes, etc. and yes, some want to run that many amps at the same time for one guitar. heck, 4 guitarists at once probably. i'm sure with the feature available, people will find a way to use it. there's always a way to use more. i personally prioritize the quality, and it's the reason i don't use other similar gear. ¯\_(ツ)_/¯what in the world would one do with 4 amps in one preset?