@faket @threemaapp Did you read the article and the comments below it?
Proton seems to have complied with a legal, valid request from Swish public authorities. If this report is true, then any company in Switzerland will have to comply with their legal rules (Like any organisation will have to comply to the local legal rules. Signal would also have to comply to a US national security letter as far as I know. Though the Signals operators always know the mobile phone number. While Threema will have a payment information trail to follow.)
A good approach for sensible accounts for Proton, Threema, Mailbox and Posteo is to pay by cash (letter).