While true,
(1) We time by IGT, and I can't imagine there's a big difference there between the two.
(2) To my understanding, PS2 is just really good, 99.9%-compatible PS1 emulation, with some small perks according to Google. The main benefit you might get is a slightly faster time RTA, especially with the fast disc speed option, but apparently that can cause crashes.
Pretty sure there are some nuances between PS1 and PS2 that the better runners are more familiar with. Though most activity right now seems to be more or less split between PS1 hardware and PS1 emulator AFAIK.
PS2s are generally better than PS1s for speedrunning, however we don't really bother tracking which hardware was used. Unless we ask everyone that ever submitted, there's not much point. As far as I'm aware most runners used a PS2. It just wasn't tracked to begin with even back on MMRTA since it was never a big deal.
