My air fryer has a spinning thing in the middle, wich turns my chips around, so i would say thats a plus!
But yea, it is basicly a small oven. Maybe it uses less energie.
By virtue if being smaller it does yes - there's an argument for using as small an oven as possible for sure - but the return on investment of that for having multiple different sized ovens is bound to be longer than the product's lifetime.
(I broke my oven door, rather than pay £150 plus labour opted to pay £280 for a new oven. That was a Bosch, certainly not the cheapest possible.)
Personally the return on the air fryer for me is a direct result of it being smaller. For most things my larger kitchen oven needs time to preheat. That's an additional step that isn't required when I just want to roast some vegetables / meat or heat some frozen potato products quickly in the air fryer. This time / extra step is well worth cost for me ($20 of fb marketplace).
(I broke my oven door, rather than pay £150 plus labour opted to pay £280 for a new oven. That was a Bosch, certainly not the cheapest possible.)