For those of you searching for good E2E-encrypted messaging apps, Wire is really good. It has true cross-platform support without being tied to a phone number.
I know a lot of folks who are technical (and non-technical) and it was a big enough struggle to get them using Signal. I definitely see the advantages of Wire and not being tied to a phone number but I just don't know anyone using it. It's odd because some of those folks are using Keybase chat though... they just bulk at installing yet another messaging app (regardless of features).
I tried to get people to use Wire but it was buggy enough, and still is with most ignored, the majority of converts have abandoned it. I have continual problems. If it would have been reliable it could have been a killer app as it was basically Skype but encrypted and ostensibly available on all platforms. Having a stand alone (no linked phone) browser (angostic) based option is a great feature. But, it really feels they left the free/Personal version in the dust for their Pro/Enterprise option and from reading Github complaints and seeing a former employee discuss it in another forum I'd assume that to be accurate. Signal isn't much better from reading around and also still requires a phone linked and is only Chrome if you want to use it on the desktop (unless I am behind the times). Seems the space for an all in one encrypted communication/sharing tool available and accessible to all people and platforms has sort of died. I will never trust FB so even if people way smarter than me say Whatsapp is safe it still feels so dirty...and again the phone required bit.
Wire's "not tied to a phone number" part is good but constant delayed messages and lack of (useful) time stamps for each message (a la Signal) make the app pretty much unusable for me (and probably many others).