Use case: your company uses Office 365, and you want your cloud storage to be integrated with the rest of the Office 365 apps, and you don't otherwise care about the quality of the cloud storage app.
I'm going to basically cede my point to you because, honestly, Office 365 is not a bad product and even though I would not personally use it, I have to admit that this is a valid use-case, haha.
I do have to point out your note about "not otherwise caring about the quality of the cloud storage app" which is more towards my point.
