Our XM817 is used almost weekly, and the M35A2 is used almost daily. We haul dirt, gravel, tents, cots, mulch, lumber, people (parades) garbage, junk, and just drive them around for the heck of it.
I don't know that they exactly make money, because we could do a lot of the same thing with pickups, but they save a bunch of time and money.
And there is the cool factor, that's worth something.
I should also add: The M35 gets almost 10 MPG, our 1999 Dodge (retired forest service truck) only gets about 11 MPG. Since the deuce will burn our waste oil, and about everything else, It's actually about as cheap to drive. It also keeps us from having to store bulk waste oil. That's one less problem to deal with on our EPA Ground Water Protection Plan.