Correct me if I'm wrong, but defrost is just a microwave for a very long time, right?
Why _not_ just microwave by typing 5 minutes? Or instead, why shouldn't the microwave have less abstruse buttons like "1 min", "2 min", "5 min" which grant you the opportunity to seamlessly jump to trying to use your intuition to figure out the timing you want instead of this vague "defrost" button which... I'm still not sure what it does.
Defrost is a long time, but at a lower power. For example, if I want to defrost a small bowl of berries I could put it in for 30s on high, but they'd get a bit cooked and squishy. If I put it in as defrosting 2oz it runs for ~1:40 at a much lower power and they're nearly as nice as if I'd let them slowly come up to temp in the fridge.
I could be wrong but I believe that most microwaves operate with a single power. The various settings are just cycling the power on and off at different variables... 5 is half the number of cycles, Defrost is a timer setting, pre-programmed based on weight of food... water content.
Yes, I think you're right, turning down the power level is usually implemented as cycling the magnetron. But you need to be smart in how you do it if you're not going to wear out the microwave unnecessarily by using cycles that are too short. If you are cooking something big you can do 50% with 30s on / 30s off, while if it's small you might need 2s on / 2s off. Hence the relatively complex controls.
Why _not_ just microwave by typing 5 minutes? Or instead, why shouldn't the microwave have less abstruse buttons like "1 min", "2 min", "5 min" which grant you the opportunity to seamlessly jump to trying to use your intuition to figure out the timing you want instead of this vague "defrost" button which... I'm still not sure what it does.