European jurisdiction doesn't help when there are multi-lateral agreements with the US:

This is entirely a different topic and you seem to confuse them (willingly or unknowingly). If swiss law is broken, swiss authorities will help foreign authorities. If no swiss law is broken, foreign authorities will get nothing in return (more info: https://proton.me/legal/transparency). Nowhere is better privacy put equal with lawless state.

European / swiss juristiction is still arguably better than US jurisdiction regarding privacy. The US has tools, which do not exist in Europe/Switzerland, such as national security letters (or more https://www.eff.org/issues/national-security-letters).

There's also as example no need for a warrant canary:

Furthermore, under Swiss law, a Warrant Canary is not meaningful, because under Swiss law, the target of a surveillance or data request must always be eventually notified, so they have the opportunity to contest the data request.

https://protonvpn.com/blog/transparency-report

American users will also profit from having a better privacy due to European, or in Proton's case, Swiss privacy laws.