This is just not true. It's terrible. It doesn't sync between the two. Working in one note is worse. It loses connection all the time. Things time out. In copilot it was a great experience that I told all our users about. Then you changed it with out any announcement or clue. Just did it. It's like your alpha testing on people in a live environment. You were catching up to Google notebooks. Then you microsofted it all up.
"Because notebooks stay in sync across the Copilot app and OneNote, users can move between the two without losing context. To go directly from the Copilot app to OneNote, users simply select “Open in OneNote.” This feature https://www.microsoft.com/en-us/microsoft-365/roadmap?searchterms=New+Copilot+Notebooks+design#Roadmap."