> If you replace office, you'll have to replace sharepoint, onedrive, etc.

At least in my workplace, people do their best to avoid using sharepoint and onedrive anyway.

Are there downsides to OneDrive?

I can see being resistant to change, haven't had issues with it (and have benefitted from the auto save quite a lot).

in corporate america, it's everywhere, to the point where people's compromised accounts being used to send phishing content via sharepoint/onedrive is extremely common. It is (rightfully) highly encouraged as well due to their built-in data loss prevention stuff (Microsoft information protection/MIP), it's the only reasonable way I've seen to get a handle on secret documents/content/slides from leaking too much.