I really like the idea of bringing your own device to school since a majority of students have a smart phone today. In our last staff meeting of the year in June, a helping teacher from Surrey showed us how he uses BYOD. Occasionally, he will put a quiz up on a site and have the students try to answer the questions. He uses it as a tool for review rather than to collect marks. If kids don't have a phone, they work with a partner or they use a laptop.
A few of my students took pictures of notes on the board or of a vocab list posted on the wall, so they didn't have to copy it down. Students can also look up images online or use a great website like www.learnersdictionary.com to look up the meaning of an unfamiliar word.
The other issue is that technology is changing all of the time, and schools don't have the money to buy 30 or 60 new Ipads every couple of years. Even then, 60 Ipads are only available for 1 or 2 classes to use. If students bring their own devices, schools don't have to purchase as many computers, and the money can be spent elsewhere.
My only real concerns are that some students don't have the money to buy the latest gadgets, so they may feel left out, but in that case, they could probably share with a classmate. My other concern is that students may use their cell phones inappropriately at times although I don't think that would be much of an issue at my school because I work with adults.