Explain to Me: Supervision within Apple Configurator

I do not fully understand the "Supervise" aspect of Apple Configurator.

Does supervising a device give you Over the Air capabilities you do not have without supervision? Can you then push apps to supervised devices accross the country that you could not otherwise do without supervision?

The Apple Configurator Manual reads:

"Set Supervision to Off if you want to configure a device once with Apple Configurator. Set Supervision to On if you intend to maintain control of a device on an ongoing basis by reapplying a configuration regularly."

What does it mean by "intend to maintain control of a device on an ongoing basis"? I plan on centrally configuring many iPads and shipping accross the country. I want to have the ability to track them and it would be nice if I could have them install apps from afar if need be...

But I also read "when you configure a supervised device, you can't supervise it or sync it with any other computer running Apple Configurator or iTunes."

Does this mean that if I supervise a device and send it thousands of miles away to a teacher only to discover it is missing a few apps, the teacher will not be able to download the necesary apps?