Judging from this

> Mailchimp may in principle be subject to data access by US intelligence services on the basis of the US legal provision FISA702 (50 U.S.C. § 1881)

It might not be just a matter of where the data is stored, but also who can get access to it. From my reading, any US based conpany would be affected.

This feels like a super huge impact that would have made more waves, but the ruling also seems recent. And perhaps there will be more twists and turns yet ?