The plumbers don't like complications.
The complication with a heat pump water heater at least, the single-unit ones, is that they are an air conditioner for the room. They are stealing heat from the room they're in. So the problem isn't that your basement is 60 degrees. The problem is that it will be much colder when the HPWH is going to town! You say "it'll come from the earth" but you might want to fact-check that belief. You're talking about a fair number of BTUs. Putting a 100 degree rise on a 30 gallon tank (250 pounds) is 25,000 BTUs.
Now you're thinking "I won't need that dehumidifier anymore". But let's think about latent heat, or the heat contained in the water vapor by virtue of it being vapor which is 1000 BTU per pound. When the dehumidifier condenses a pound (pint) of water, it adds 1000 BTU of heat into the room, because that is the latent heat of vaporization of water. That had to go somewhere, and it's not in the water vapor anymore - it's in the room now. Assuming it's working at 4 COP, it also adds 250 BTU of heat from its own mechanical function.
One reason the basement is 60 degrees (and not colder) is that 1250 BTU added to the room per pound of water condensed. You're going to lose that. Those BTU will now go into the hot water tank. In a 30 gallon (250 pound) tank, that 1250 BTU will raise the water in the tank 5 degrees F.
So yes, I am concerned about basement temperature, and I think your assumptions of "it's 60F because it's in contact with the earth" may be incorrect.
Now, a much more difficult thing to find, but certainly solves this problem, is a "mini-split" heat pump which has (as one of its heads) a water tank. Now, the heat pump lives outside and is taking heat from ambient outside air. If you think heat pumps don't work that cold, you're thinking of decrepit old American tech. Others have lapped us with new technologies using new refrigerants, that work just fine and sustain 2.5+ COP down to Chicago cold. That's why so many buildings in Ukraine have mini-splits on them.
If you're wondering how heat pumps can work that cold, think in Kelvin. It is numbered from absolute zero, which is what REAL cold is. -10°F is actually 250°K and we enjoy home temperatures of 295°K. Water tanks are best kept at 333°K.