That's true until the compressor starts running...at that point if you're using more air than the compressor can pump, it will run continuously. It's hard to get a reasonably priced compressor that won't run continuously when sandblasting, or even using a die grinder. Mine is an IR and it runs a lot. So the tank size is pretty much irrelevant when you're using a lot of CFM. But I agree that at 175PSI and a large tank you store more air. I'm not sure it's worth the consideration though.
True on the cooling, but if it runs a lot even a larger tank is going to get hot. The air heats up when compressed, and it is transferred to the tank. It doesn't have to be very hot for the air to retain moisture.Also a larger tank gives the compressed air better cooling to separate the water at the tank (dryer, cooler air) About the largest HP 220V single phase motor made is 7 HP, although 5 HP is much more common. Get the largest CFM and highest pressure you can with one of these motors.