OP - the way I look at an air fryer is to compare it to a microwave. MIcrowaves are very handy in that they allow you to do certain things very quickly - you can defrost foods that would otherwise take hours, you can heat up leftovers very quickly, you can quickly boil/steam veggies etc.
The airfryer is the same but for things that you would usually use an oven for. So it's a time saving and convenience tool rather than offering up a whole host of new foods/cooking techniques.
Like others,we use ours a lot and also often for smaller things that would just be time consuming and wasteful to heat up the oven. For example, yes, the crumbed chicken/fish fillets and chips from the freezer for the kids in my Ninja takes just 12 minutes vs 9 minutes to pre heat the oven then 20+ minutes to cook. This is particularly helpful on days we're all eating at different times - relevant person comes in and sticks their fish fillet/fish cake/chicken fillet in the air fryer and microwaves whatever sides I have prepared earlier. And not just freezer ones - I regularly prep salmon fillets and they take just 6 minutes in my air fryer so as me/dh/ds come in we turn one on and are eating less than 10 minutes later.
I use it a lot for things like par-baked bread as a way to get a quick fresh loaf/roll/ciabatta out quickly. Similarly frozen uncooked croissants - takes 30 minutes in the oven by the time you've heated it up etc. 11 minutes in the air fryer.
I also use it for smaller things that I don't want to use the oven for - eg I will roast some cauliflower in there to add to a curry this week as it's quicker and easier. I regularly roast tomatoes and onions (takes about 20 minutes) to have with couscous and feta for lunch. Similarly, jacket potatoes can be microwaved for 10 minutes then put in the air fryer for 20.
Its also very handy when entertaining. my big oven might have a roast or a large lasagna but the air fryer is churning out little canapes, or fresh baguettes etc.
edited to add: I have a single drawer one but I am eyeing up a larger/double drawer one and one thing I will be checking carefully is I quite often freeze lasagnas/curries etc in single portions in foil containers. They are then heated up in the oven but it's faff and takes ages. I'm definitely aiming for a drawer that can fit one of those so that when someone eats one of those meals, they can use the air fryer. I suspect it will half the time it takes to cook from frozen.