I agree that it looks like a tool used by Carl Spackler (Thanks Ric!)!!
It can be a useful tool for those that want the critter's gone and now!!
It may be noisy.......and messy but with a tarp placed in strategic areas, the mess is minimal.
As far as the bang......as long as it is within ordinance and with license......who cares.
I consider the bang as an attention getter to generate business. If those moles are gone, then money is to be made.