Because it doesn't work. Tried on a galaxy tab 4, a Tab A, and a GS5, and nothing works. The device puts me out $30, but at least I didn't pay $80 for the full software.
I'm sure that Thursby's response will be to make sure I have downloaded the most current software. ..that's the only response ever given in this forum.
For the record, I did check the software version. Still no joy.