It is similar in function to the victoria/corona mills that some people use with good result. Here are the problems I anticipate, however.
1. Coffee beans are much large than wheat or barley grains. As such, a burr grinder for coffee may work poorly with smaller items.
2. The fixed speed of the motor may not be ideal and would not be (easily) adjustable.
3. The capacity would be small.
I think for not much more money you can probably find a corona type mill which would work better.