Those are not really updates, but small patches of that version to fix installation issues.
In regards to uninstalling and reinstalling for an update it has actually been like that since Nero 8. Nero is like the only software that I know who says it’s an update but is the full installer. I think the control center is supposed to check for updated components. So if Nero Express had a change, only that component would be updated. At least I think that’s how it should be.
There really is not much of a difference between Nero 8 and 9. They got rid of some programs from 8 and made them separate purchases. Also from now on if you have an oem version of Nero 8 or earlier and need to just buy the plug-in, too bad because they don’t exist anymore on the site. You know must upgrade to Nero 9 if you want the mp3 plugin or dvd authoring option that doesn’t come with most essential (oem) versions.
I think there has been a drastic decline in Nero product quality since around early 2008. JUst look at the Nero Company History, that might give you a hint.