Sure, its not an attack for every situation and requires a lot of setup, but if used at the right time with cards that get Dreppy out quickly, you can catch your opponent off-guard and maybe even take multiple Prize cards
If an ability triggers "whenever you roll a die," it will trigger whenever you roll any die, including the planar die
I have seen it happen back when I was a total n00b, and it was shocking to see this little thing get big and then proceed to kill me, especially in limited, but I think you can even get it to be big in constructed
The most playable and desirable such cards will of course maintain a significant premium
So this single card, which has a single entry in Gatherer, actually has 10 total distinct printings for our counting purposes