Pi has the power to do up through PS2 just fine, though last I checked the state of emulation for PS2 and PS3 wasn’t good yet, for the average hacker.
If this is your first time emulating, you’ll have a nicer time learning the ropes on RetroPi on an actual Raspberry Pi. Statistically, you’re not really giving anything up, because anything that doesn’t require insane levels of expertise and esoteric knowledge emulates perfectly on Pi.
Contrarily, is this isn’t your first emulation outing, or you’re down to go all-in down the rabbit hole; then build the whole PC around whatever you find emulates PS3 well, and the rest should be trivial to add.