Not an unfair comparison, though I find Obsidian overly complex/convoluted. But I think that comes with the territory when your design philosophy is very open extensibility and using standard document types rather than a proprietary binary format like ON.

Plus OneNote is 20 years old now, was extended (after MS bought it) to integrate with SharePoint (maybe it was designed that way, I don't remember), so really is a 20th century piece of software. There are add-ons that greatly extend its capability (Onetastic, Gem, etc). So in a business environment the full desktop app with SharePoint is pretty impressive. To it's credit, I have 15+ years and gigabytes of data in it, and have never (knock on wood) lost anything, moving it across perhaps a dozen systems.

All that said... I'm moving to Joplin, lol. Trying to get away from dependence on apps I don't control (and I want a notebook that works on Linux too).

To sync to mobile devices, OneNote requires Onedrive (or setup your own SharePoint server, uggh). At least with Obsidian/Joplin, etc, I get to manage how things sync. And if I'm happy with the features in my current setup, I never have to change anything. Never know when MS will fuck up Onedrive sync, requiring a version of OneNote I can't run, or has issues.