Personally, I like the heater in case engine temps get high, as then it acts as a secondary radiator, even if it will make the cabin super warm
I am not sure if the water pump will like having that coolant intake shutoff, or if the intake will like not having that coolant leave from the heater port. Both the radiator and heater feed into the same side of the impeller. Normally when a heater bypass is done, you feed the heater core input straight into the water pump so that the coolant still flows like normal.
So I guess, I am not sure sure if it will work or not. But I never bothered doing it, and I drove without AC here in 100+ temps.