I have never heard of this type of device. It sounds like a great idea. A lot of folks do all their banking over the internet and use ATM cards for local purchases. I haven't written a check in months and hardly ever carry cash any more, lol.
I have a personal check writer. It's taken me 40 years to get her trained (sort of) but she doesn't fit in my pocket.
Seriously, I find that my bank debit card works pretty well in situations where i have to pay something.
Sweet Ol Bob