I assume they are launching this due to the recent news about WebKit removing support for progressive web apps (PWAs) in the future. This is also probably a move to compete directly with apps like Slack that already have desktop applications.
I would be really enthusiastic about this and install it everywhere if I was a Facebook Workplace customer, but I don't see the appeal from a consumer standpoint. There's a lot of potential for undetected data collection that can be done with a desktop app with permission to access video and microphone. I guess you could say the same about Slack and Microsoft Teams, but they have a better reputation for how they handle data they collect from their customers.
Ignoring the privacy issues, the consumer market for Facebook Messenger has already installed it on their mobile phones and get notifications there. If you need to write out a longer response, go to the website to type it out.
