If you are on a certain data plan on your mobile provider, and don't want to exceed it, you can set data usage warning and a limit which can help you save some of your money.
If you are afraid your friends, kids or any other person you are borrowing your iPad to, might delete an app by mistake or even intentionally, you can enable restrictions on individual all of the apps.
In case you just upgraded your iOS powered device to iO7 or any other version and now this device runs slower than it used to, this resetting of the device procedure might speed things up.