At a minimum I would say any new SRS app or site needs to be Anki-compatible. It just has such a big lead in terms of mindshare in the space - though I agree with other comments that it definitely has some seriously dated features. Any interest is the space is good imo.
I’ve been looking into adding the ability to import sets from Anki, especially with how widespread it is. We already have it for Quizlet, but Anki will certainly be next to be able to be imported from.