And it's obsessed with slurping your data up to Microsoft. If you want to stick with an older (unsupported) classic Desktop OneNote, you get a modal dialog box every. single. time. you. open. it. saying "Get more out of OneNote. A newer version of OneNote is now available for free. Go to www.onenote.com to download."
On the plus side, if you do use Microsoft Cloud storage then you can query and work with the OneNote data through the MS Graph REST API: https://learn.microsoft.com/en-us/graph/integrate-with-oneno...
So you can programatically add and update content in pages in a shared team notebook, for example. And because it "runs" in MS cloud it supports things like asking the cloud services to "screenshot this webpage for me and add it as a note" and "extract content from this website and add it".