How are you framing this? It’s an Electron app so it exists but doesn’t integrate or perform great. Last I recall you still were required to provide a SIM to sign up & you needed an iOS or Android primary device to even use the desktop client. Can you use a standalone, fast desktop application like you can these other protocols? I would say no, so “support” has shades of gray to it.
This is how I got kicked off LINE… they had a Chromium app that I could use tethered to an app, they disabled support for LINE Lite (which had light/dark theme, E2EE, texting, voice/video calls, debatable trackers (Firebase), even stickers & sending a location @ 8MiB instead of 200MiB+ of the “heavy app”), I refused to “upgrade” as it was a downgrade to me, & since I was no longer registered with a “primary” device, I was booted from the network. I don’t think I want these mobile-duopoly-required apps to be my primary means of communication with folks—especially now that my primary phone isn’t Apple or Google (luckily Open Whisper lets WhisperFish exist).
The Signal desktop app works fine, but you are right, it is still tied to a mobile account and a phone number. This is the main downside to Signal. I read that the Molly fork will support multiple accounts and a self hostable server. It probably won't be federated, but that is not really a problem when you can use multiple accounts and avoids a lot of headaches that come with federation.
> but doesn’t integrate or perform great.
Curious what you mean by this. I use the Signal Desktop app. It does what it's supposed to - send and receive messages in a timely way with no lag.
What poor performance are you seeing? What doesn't integrate?
The other downside of the Desktop is that it requires periodic re-verification with the device you used to set it up. Desktop users are definitely second class citizens in the Signal ecosystem.