I'm always amazed to see people bend over backwards with really awful emulation just to get their grubby paws on retro achievements. Like, the gamerscore pull is a completely foreign concept to me. It's nice but it's not how I get enjoyment from playing a game. Wanting me to do stuff I otherwise wouldn't try in a game is fun, but... I can just sit down at a console and do that. Other people could do that with a MiSTer, or just a better emulator. I can do the same thing, I just don't get a little checkbox afterwords.
Or just people willing to deal with RetroArch at all. That still astounds me. You'd think everyone would have scuttled it by now but, nope!
Shoutouts to Duckstation and PCSX2, which I think are the only two standalone emulators that support achievements. They're also, coincidentally, really good emulators.