Definitely doesn't make sense. I use hangouts constantly. It is my default app for SMS and chatting with family. I like having one consistent thread between different desktop devices, as well as mobile. Yes Slack has replaced it for work, but that's no good for family, at least not mine. Until this has desktop support there is no reason for me to buy in. Why not have (one of) the most important feature of hangouts (and all of the other competitors) on these new apps?
For SMSs too? On my Android, the new(ish?) message app ("Messenger") now wanted control of SMSs back from hangouts. Another silly reversal, and another silly messaging app from Google.
Fourth time lucky?
On that topic, when is the inbox app replacing the gmail app?
Maybe never and that's good, given that sometimes I cannot download attachments with the inbox app that I can happily download from the old gmail app right away.
Google wants to own the whole IT stack from servers and software services to devices. It supported the entrenched alternatives (Windows and Macs) when it had no alternative, but now it won't, unless it really has to.
In Google's thinking, the whole IT stack is Google cloud-based, and in the long term, people having "different desktop devices" isn't the right way to go.
Yes, this is overstatement for sarcastic effect, but the trend seems to be real....