QR codes, are they really useful?

Searching and searching, I have found this interesting technology called QR codes. The Quick Response codes by which you connect your cellphone to a webpage, a text, call to cellphones or just send a sms. Interesting! and its use at school seems to be a good way to call the attention of the students. Specially the treasure hunt activity, in which the students go around the school searching for the QR codes that you have pasted already, and they have to find the information with their cellphones.

Until here, QR are awesome. Then I could find a programme to my cell, and it worked, great! Then I found a generator (qrcode.kaywa.com) and it worked too, so much great!

But now, I understood the cruel reality. Does QR codes really work for a teacher? I mean to say.. are they really useful at the school?

For me.. unfortunately.. no. Why? Because, first of all, this is a new technology to be applied at the classroom, and most of my students don't have a modern cellphone, and in addition, you need a connection to internet and of course, you have to pay, unless you are connecting to wifi. But at least, in my school, wifi is not available for the students. and I think, that even if it is... how can you connect too many cellphones?? And I feel that once they can connect to wifi, they will not be interested on QR codes.. but on facebook, right?

I think that activities generated by the use of QR codes at the school are really interesting, but it takes a lot of effort and time to implement it, and unfortunately, it is not applicable in my school.