There would be old coolant sitting in there unless you blow it all out using compressed air.
It’s nice to have heat and be able to defog your windshield, personally I’d want a working heater setup.
When you’re on the verge of overheating on a very hot day I suppose it’s a good thing to be able to utilize that heater core to try and take the edge off, and cook your feet a little at the same time.