Do you mean Oxen? Not all that many people use it apparently. I use Session messenger but it’s not super reliable… Although no worse than Matrix I gusss.

I do like the decentralised onion style of networking with no reallife identifier, for obvious reasons. There’s some crypto mining involved (like legit opt-in for which you need to set up a node, not something secret on the background) which may sound dumb, but imo it gives people the incentive to run nodes and widen the network. Unlike Tor where the incentives are… None, unless you have a specific reason to run a node.