> While it's interesting, I'm failing to see what the use case is.

I'm unclear if it supports relay mode, but if so, you can invite Matrix, Signal, and WhatsApp users into the same group chat! [1] Edit: Relay mode is not currently supported in Element One, I tried it out. I contacted support and they said "we will discuss this internally and possibly enabled it later"

I've been using this on my self-hosted version of the bridge and it does wonders for those friends who are on Signal but don't want to try another app.

Also, a lot of people just don't want to swap between apps for direct messaging people on different services. This means you can use any Matrix compatible app [2] to chat with anyone on Matrix/WhatsApp/Signal/Telegram.

[1]: https://github.com/mautrix/docs/blob/master/bridges/python/s...

[2]: https://matrix.org/clients/