Well that's nice and all but i don't really see the point with so many better standalone psx emulators around.
If means better accuracy for ps2 emulation,considering emulating psx games is a side product of this improved accuracy.
How? considering the ps2 was using actual psx hardware it had built in to to run psx games, they where not running on the emotion engine like ps2 games.
"The PS2 runs PS1 games using a combination of hardware and software emulation. The sound and I/O CPU in the PS2 is the same CPU type as the main (and only) CPU in the PS1. This CPU and the PS2 sound and I/O interfaces (to controllers, memory cards and the CD drive) can be switched into a mode where they emulate the PS1 CPU and its corresponding hardware interfaces, hiding away all the PS2-specific registers and capabilities. Meanwhile, the PS2 main CPU (aka the Emotion Engine) runs a software emulator that emulates the PS1 graphics hardware. The emulator is built into the PS2 BIOS.
In short: graphics are software-emulated, everything else is running directly on the bare hardware. That's why you need a PS1 memory card to save PS1 games."
ps1 cpu doubles as the I/O processor when used in ps2 modo, so it helps ps2 games too.