That looks a lot like a server hosted by somebody else in a data center.

It's also way more hassle than almost all of my contacts would be willing to go through, and if only I self-host but they don't, it'll be Gmail all over. (Almost all emails go through Gmail because that's what at least one of the parties in an exchange is likely using.)

Point-to-point encryption is not enough for messaging in today's network topology.

> just use Telegram

No thanks, I'll continue using one actually spending some effort on not being able to read the messages their users send.

Fortunately most people in my country do. Ironically it's only a couple of people in my circle of friends worried about the privacy of said messenger switching to Telegram "because it's encrypted"...