Are Notes stored in the “on my iPad” section included in a device backup

I created some Notes that were in the “On My iPad” folder, rather than in the iCloud account. Then I wiped the iPad, performing a device backup as prompted beforehand. Should I expect those Notes to be part of the backup? They don’t appear to be there when restoring the iPad from the backup, but I can’t understand why they wouldn’t be. Is this a lesson that device backups might be less complete than I expected?