Microwave: either stand and wait or get up again when the thing goes off in five minutes. You have chronic pain or just had surgery or are just brutally fucking depressed or devoid of executive functioning that day, so this is an issue.
Delivery: get up once. It's more bearable and saves you spoons you could maybe use to stand and brush your teeth or something later.
Microwave: you have used the last thing in the fridge/freezer and can't go to the store to get more until tomorrow or the next day.
Delivery: you still get fed.
Microwave: harder to prepare food for several people because the inside is small, does not typically yield leftovers.
Delivery: food for everyone, could yield leftovers.
Microwave: food texture can be terrible, soggy, tough.
Delivery: preserves the small pleasure of crisp, well-prepared food.
Microwave: have to cook several times a day, which is a chore from frozen.
Delivery: you can order food to last you all day, and get larger and more calorically dense meals. (If I can only manage one meal, yes. I do in fact need it to be full of calories. A 450kcal microwave dinner isn't enough to live on.
Microwave: relies on you having a fridge/freezer.
Delivery: sort of relies on you having a doorbell, I guess?
Microwave: on average, quality is unappealing.
Delivery: wide range of appetizing foods, including healthy foods.
Delivery: you might see another human's face and pass a few words. Boyfriend did delivery. Don't laugh. People get fucking lonely. Yes. That is very sad. Meals on Wheels type programs that deliver regularly are a major source of socialization AND safety checks for shut-ins.
Microwave: you suddenly need a different kind of food than you have -- you might need soft food because your mouth hurts, plain food because your digestion is iffy, soup because you've been ill and aren't up for much more, etc.
Delivery: order whatever you like.
The smallest barrier can be enough to make me skip a meal or two or even three. People HATE that, they HATE the idea that disabled people are "weak" and "lazy" but I cannot emphasize enough, NOBODY WOULD CHOOSE THIS.
Laziness, in the way temporarily nondisabled people apply it to sick and disabled people, doesn't fucking exist.
Don't judge or question what people eat, when, how they prepare their food, where they get it, none of that.
Just because you cannot imagine a reason for something sick or disabled people do doesn't mean there isn't one. If something seems baffling or absurd or whatever, just be glad you aren't operating under conditions that mean you have to understand it.