Most emulators focus on compatibility first, speed second. Only because most people just wanna play their favorite games and everyone whines when X isn’t emulated, but as compatibility gets high, many emulator authors go back to streamline the emulators. It’s what happened with GBA and SNES emulators at least.
What is probably the biggest point of concern would be how long they stay with it.
The dreamcast had a lot of great games and it’s a shame there wasn’t a way that once sega shut their servers down, control could have shifted to people providing their own servers. (Since if I recall correctly JP versions of some of the fighters had matching service to play against each other.)
I believe it’ll happen eventually but it’s hard to say whether eventually is three years or ten.