I tend to use it to finish certain foods...
For instance, french fries. They can get greasy when deep fried but deep fried flavor can't be beat. So, I deep fry them but take them out before finished. I then toss them in my airfryer. They crisp up nicely and excess oil drips off.
I also use it to warm any left overs that would get soggy in a microwave. Like... fries, hush puppies, catfish, pizza, basically anything with a crust or is crispy or is breaded.
I have a new oven that works great, very precise and its winter so I don't mind heating up the house. I do use the airfryer more in summer for that reason.
I also use it when speed is required as opposed to my oven, meaning I don't have extra time and need to be somewhere.