I dunno, a while back when Google launched out Inboxy by Gmail, I was pretty stoked. It looked like a new, pretty way for me to manage my Gmail accounts. Took a while for it to reach my G Suite accounts, but by then I had lost my 'interest' with the app.
I don't really know why I wasn't more enamored after a while. Maybe it was the limited ability to folderize (I love moving emails around) and a bit of a confusion around 'done' ... but it just never took off for me.
I tried using Inbox on one device and Gmail on my other and I just preferred Gmail. Especially after recent updates (yay, updates).
Well, maybe there are more people out there like me, as Google is shutting down Inbox in March of 2019.
Were you using it?