I don't see the point in buying something that does what I can already do very efficiently, which is fry things in hot oil. I've also already got an oven, so why would I want to buy another one?
"Fry" is defined in most dictionaries as "to cook things in hot oil or fat", so when you "air fry", you spray the food with cold oil or fat, right?
I agree it might be convenient for one person.
As for "energy saving", I wonder how much energy you would effectively save over a month. Would it really make a huge saving on the electricity bill?
I've got one, however (my wife uses it) and I absolutely respect anyone who wants to have one