After recent US shenanigans why would you spend effort to migrate to yet another Five Eyes controlled service, especially if they do the full "privacy from Germany" circus.

What kind of security threat does a migration to such a service actually mitigate?

If they were truly a "sovereign EU" kind of project then they'd be on .eu domain, not have security advisors from Virginia, and so on.

Nevertheless it's good to see that the decoupling-from-your-allies movement that US citizens have initiated is so scary that they have to set up these kind of fake EU alternatives with some local figureheads.