@plonerma They’re talking about what they are offering as part off their service as an email provider, and specifically this page is talking about the drawbacks of using their service. It’s actually one off the funniest and most honest pages where an organisation explains why I shouldn’t their own service that I’ve seen.
This section ends with:
"If you are interested in real encryption and absolute security for your Santa letters, please use end-to-end encryption tools such as GPG with your correspondents or pull locally all your messages periodically (e.g. via POP3) and encrypt them yourself on your local device."