While certainly my ROG phone plus gamesir is enough to even emulate this gen’s handheld games. It cannot beat playing a gba game on an Anbernic rg35xxsp.
Second is that some owns a low tier or a very old phone and they don’t want to throw it away because it still works perfectly fine.
So instead of spending 300 bucks for a decent mid tier phone replacement, plus accessories, spending 99 bucks is far more cost effecent.
Then there is that storage issue. Some newer phones today no longer have an sd card slot for expandable storage.
Plus some if not all of these handhelds are moddable as fuck too.