you can use original ps1/ps2 discs with an emulator too.
not really an expert on the subject, but I think GCN emulation is considered to be pretty good, and PS1/2 emulation isn't perfect yet but probably passable
I havent looked into the current state of PS1/2 emulation, but its been passable for many years now.
It's like paying for bubble wrap. -transience on Final Fantasy: All the Bravest