ew, 99.9% accurate emulation? BSNES is as good as a real SNES, both literally and in terms of convenience.
I'm not really a huge emulation snob (though I do use only real hardware mostly, including for SNES).
The problem is lots of emulators is latency, and scaling. The latency issue can be exacerbated when you try to get analog out on lots of platforms these days, and the scaling too!
The original classic consoles run in a wide variety of modes (timings) like 256x240, 320x240, 320x480i, 640x480i, 720x480i, and in slightly different aspect ratios. They render to frame buffers (when they actually HAVE frame buffers) using those resolutions but also oddball stuff like 256x212, but this can be addressed with blank lines (larger vertical blanking interval).
Can a Pi output that via 256x240 via RGB? HDMI? Nah, it's getting scaled to 640x480. This causes visual fidelity to suffer.
There are more resolutions than I mentioned, and if you throw arcade in there, forget about it! There are tons more.
Something like an ArcadeVGA card can output all these modes in RGB, and present the proper frame buffer to the emulator to render do. Here are
just the 240p modes that it can output natively:
240x240
256x240
288x240
296x240
304x240
320x240
336x240
368x240
392x240
448x240
512x240
640x240
A Pi is going to scale a lot of the time. There's a reason a bunch of people went nuts for the new pixel-accurate mode for SNES games on 3DS. Because the scaling really hurt the image.