Delta Putting WiFi on Planes Part 2

Ok, now that I’ve thought about this I’m left with more questions:

1) Why will I be able to use WiFi on a plane but not Bluetooth? I can’t imaging that they are only shielding the plane’s electronics against certain frequencies and I’d really like to use my BT headphones.

2) Why can’t I use external WIRED USB peripherals like a USB Hard Drive? (Hint: it’s specifically prohibited in Delta’s magazine.) Does this odd prohibition mean that I can use a USB WiFi connector?

3) If it’s shared WiFi among the plane and everybody uses it on a 767 will it slow to a crawl? If it does do I get a refund?

4) Since it only works over land, will Delta be smart and not let you buy it for a transatlantic flight or will they be dumb like they are today and simply tell you not to. (As an example, you can buy a 2 hour movie on a 1 hour flight but they make announcement and tell you not to.)