Just in case anyone was wondering about why only Higan, BSNES, and the SD2SNES are allowed for emulation:

The gist is, after 40 minutes, SNES9x is over a minute ahead of all the others, and after only a few seconds is very visibly out of sync with some specific early timings.

Other FPGA solutions need to be tested, but I can confirm that no other well known PC SNES emulator is accurate enough. Most other Super FX game boards either ban unofficial emulators or require highly accurate emulation as well.