This is a very welcome feature that saved my day at various occasions, you can turn your iPhone into a wireless hotspot and share its mobile data connection.
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.
A really useful feature in case you want to receive a warning notification before you use all of the mobile data available according to your mobile provider contract. It's a great way to avoid additional charges.
You can easily copy any text on a website and then paste it to anywhere you like on your iPhone or iPad iOS powered device. I will show you on a website to email example.
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.