They were, but now you can play Majora's Mask with dual analog camera controls and there are fewer errors because you aren't emulating a 30ish year old system.
They were playable, but the n64 emulation is known to be extremely hacky and far from good even after all these years (glitches and bugs are still noticeable in some games).
The recompilation project is a huge improvement in every aspect because it goes beyond making a game playable and seems fairly accessible to those who have the knowhow, someone already recompiled The Mystical Ninja Starring Goemon, a game that is not exactly popular, and it runs and looks pretty well (for a n64 game, that is).
I believe Goemon is a pretty popular game in retro gaming circles. It comes up on many people's "Top 10 N64" games or list of "hidden gems" on the console
I feel like there's a lot of overlap between the people who are interested in the recompiled ROMs and the people who are involved in N64 discussions on the internet, haha