Can I Power Heat Pump Water Heater with Unused 3 Prong Dryer Receptacle?

I am considering replacing my natural gas water heater with a HPWH. There is an available 3 prong 30amp dryer receptacle from when I replaced my dryer with a heat pump dryer.

Is it allowable by code to get power from the dryer plug either by adding a 3 prong plug to the HPWH or by removing the dryer receptacle and hardwire to the HPWH?

Also, I am still not quite set to going HPWH. I expect the financial aspect will be a wash. Running cost of natural gas will be about the same electricity used by the HPWH. I can't drop natural gas entirely due to the furnace and backup power generator. The benefit I see are: no more combustion of fossil fuel within the house envelope, allow for better insulation of the house from heat and dust, and better synergy with whole house solar and battery in the future.

I am still not sure if it's worth the >$1000 upcharge for the HPWH though. The noise is also a concern since the laundry and water heater room shares a wall with the living room.

Would you have still gone with a HPWH if it didn't save any money?

Thanks for any input.