My evenings are a bit frantic but I have lots of time in the mornings.
I have a large freezer, and usually shop from the yellow sticker aisle of reducedness. Microwave is marvellous for defrosting large blocks of meat and fish so that when I do have time to cook I can do so without having to go back in time to defrost things overnight.
I then make big batches in a morning, divide it up into that which will be eaten tonight, and that which will be put into single serving containers for the future. The microwave is great at cooking those single servings from frozen in minutes, useful when a child needs an early meal before Scouts or comes home starving.
Emergency sponge puddings.
Steaming veg.
I don’t like microwaved eggs or porridge so I’ll take the pain of scrubbing the saucepan for those. But starting off baked potatoes or steaming them for mash, yep, or, I will do a dozen or so at once in the oven (always seem to taste better when cooked in bulk), split them and freeze them in halves with baked beans and cheese already added, 2 minutes in the microwave instant meal for starving teens.
My mother does all sorts including bacon and burgers (yuck), suet puddings (yum), making jam (hmmm).
I could live without it. But I do find it very convenient, especially when we all need to eat at different times.