> And why is having a data center in Germany a selling point for some of these email providers?

The EU, and Germany especially, have strong privacy regulations and laws to protect their citizens. Having a datacenter in the EU does not mean that your data can't be accessed by authorities at all, but it's harder than in other countries. At least in Germany, a judge-signed request with a specific reason is needed to get data from any email provider. Mailbox even publishes a transparency report[1] with details about said requests: in 2021 they just received 65 requests, 15% were incorrect. 61 of those requests were just about the contact data of the account owner, not even emails or any other data stored.

[1]: https://mailbox.org/en/post/transparency-report-2021

> The EU, and Germany especially, have strong privacy regulations and laws to protect their citizens.

This could quickly be changing with proposed mass-surveillance "Chat control" legislation which would force all providers to scan the contents of all messages, emails and other communications.

https://www.patrick-breyer.de/en/posts/messaging-and-chat-co...

The german provider posteo publishes every year anonymized requests and why they denied them.

I use Tutanota and it's... fine for my needs. The web app is ok but it'd be nice if there was something like Proton Mail Bridge [1] for Tutanota so I could use my own email client.

I guess having data center inside EU could be a plus for EU citizens?

1: https://proton.me/mail/bridge

There's also StartMail based in the Netherlands.