Sometimes Apple products can be annoying when you don't use them as Apple expects you to use them. In this situation, Apple expects you to sync with a computer/itunes with the same itunes user that you used to buy apps & whatever in your iPad.
If you do so, it makes a full backup of everything, DRM protected or not (and if you bought songs or movies, they appear in iTunes). In fact, as you discovered, it comes quite handy to backup from time to time just in case anything happens to the iPad. It can also be used to migrate to a new device (ex. if you get an iPhone or a new model of iPad, you can restore your backup to the new device so you don't loose anything).
Sometimes Apple products can be annoying when you don't use them as Apple expects you to use them. In this situation, Apple expects you to sync with a computer/itunes with the same itunes user that you used to buy apps & whatever in your iPad.
If you do so, it makes a full backup of everything, DRM protected or not (and if you bought songs or movies, they appear in iTunes). In fact, as you discovered, it comes quite handy to backup from time to time just in case anything happens to the iPad. It can also be used to migrate to a new device (ex. if you get an iPhone or a new model of iPad, you can restore your backup to the new device so you don't loose anything).