It can improve users confidence/trust and Proton transparency, once Proton gives users in their account an overview page which would be showing all user's non encrypted sensitive data that the Proton is aware about and can share with Swiss authorities.

It is quite complicated to figure out what Proton knows about me and makes user not confident about using Proton.

On that page, user would see for example:

Recovery email: a@b.c [change/remove]
Recovery phone: +123456 [change/remove]
IP used in Simplelogin/VPN/ZenDesk/contact forms (if is collected): 1.2.3.4
Financial information used to pay for the service with gateway XY: abcdefg [request delete, delay X months/delete in progress]