is this garbage necessary?

Sorry but I still don't get it. Are u guys saying if I removed the discussed valve I will always have heat in my passenger compartment, or in other words a " hot core" all the time. I don't see how that's different than every other mopar i have owned that has water continually flowing through core.
I guess another way to ask is how, in all my previous mopars ,(which were all non-ac cars ),and always had a "hot core", what kept heat from continually filling passenger compartment?? In those cars was there a similar valve tucked up under dash?? I understand how if the core was continually hot that would sort of counteract the ac, but ac equipment has been gone for a long time.
Pardon my confusion and generally low grade of intelligence. Must have had lead in the water pipes of my school as a kid.
Neal