No linux version. I was almost convinced that this was going to be another Electron app (after slack went that route)
Edit: Tried it out. It's visually pretty but it wouldn't even let me add my Slack account (we use SSO, maybe they haven't updated for that). And then when I clicked the Send Email to Franz, the email was prepopulated with some social "download franz!" message.
Edit:
Still pleased to use it, I don't like the Skype client for Linux.
It being a collection of wrappers is either true or not and is not necessarily a value judgment, but a technical detail.
And so far, I've not seen any differences or platform specific bugs.
Sure, you'd expect a big company like WhatsApp to do QA testing on every platform they release for, but it's a shame that even with the barrier of entry is so negligibly low, that they still won't provide a Linux build. Even if it's just for the latest Ubuntu LTS that's fine, other distros can repackage it themselves.