You don't need to but the developer recommends that you wipe your device. This is a drawback which you must bear with if you want the latest tweaks and customizations. If you do not want to go that route, then wait for official google updates.
You could also use Titanium Backup to make a backup of your apps and after installing an update, just restore.
Ok but Titanium don't restore all my configuration ( I change all Light sensor ... )
Sent from my Transformer TF101 using xda premium