Well I have to admit, those are some pretty snazzy tricks...
Using tor on a per app basis is pretty cool, I wonder what the security implications are for that? If some, but not all of your traffic is going through tor, I wonder if it's easier to disentangle somehow... Probably it's still secure though.
I am just sad that the desktop version is not as full-featured. The website says no Tor bridges, which here means no Tor connectivity at all. And it is weird that the mailbox is primarily for phones, even though phones are not supposed to be working permanently on a charger - they do have a cli one at least so you's probably be able to use something like a Raspberry instead, for now only buildable from source but hope it develops. But yea, very cool model! Although I would say for everyday less sensitive communication I would choose XMPP or Matrix instead.