Due to the type of work I used to do, I required various messaging apps and I have to admit that it is quite tiring. Almost every group of users is used to a different app, for me it was torture between all of them. Damn notifications.
If something could unite several platforms, it would make sense for me and such a thing would make my life easier.
I am only aware of one such app - Mixin Safe.
I remember that very bad story, although they just started to appear on the Btt forum. It seems to me that the moment they drew attention to themselves, hackers found a loophole and cleaned out their wallets. Which were safe until then, as the name suggests.
Didn't Gbyte, later rebranded to Obyte, have similar functions even sending their coins via messages or email?