One showstopper for me is that Jujutsu doesn’t support .gitattributes (https://jj-vcs.github.io/jj/latest/git-compatibility/).
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to the extent that niche things might not be supported (yet), so be it. It suits the needs of the vast majority of people. Moreover, if you need those things, I BET you can just do it via git and then carry on working in jj, since jj sits on top of git