You are right, that is one monster tow vehicle. I have seen similarly spec'd trucks when looking at extreme boats like the cigarette boats or outerlimits they come with tow vehicles like the one you linked to. I guess when you blow a million on a boat what is an extra 100k for a truck to tow it?
I would think a used Class 8 semi would have more tow capability, cheaper to buy, and be cheaper to maintain in the long run. Note the trucks GVWR is 26k lbs, the magic breakpoint for not needing a CDL to operate.