Eh, it’s not usable as an inbox. It doesn’t exist on iOS. It still groups by channel, and if you read anything or click into something then you lose it (dealbreaker for me).

Whereas with my email inbox (which works the same on desktop or phone), I can read the messages without losing them. I can read all the new messages, work on the ones that are most important and earliest, and only when I’ve dealt with them do I archive them and remove them from the list. That way I can always look at my inbox to see what needs to be done (not what I’ve yet to read).