I watched the "air fryer" demonstration again and it looks like they're just rebranding an old technology. Their function is similar to the portable convection ovens with the glass bowls from the '90s. We bought one to use in our camper 17 years ago and loved it for roasts, chicken, veggies... never tried french fries.
So, I pulled out a bag of Ore-Ida crinkle cut frozen fries and my old portable convection oven. I sprayed the fries with Pam Original, used the upper rack, 425 deg. and 20 minutes later I had delicious crispy french fries.
The glass bowl with mine is heavy. If these new appliances work as well as my old one, I may get an "air fryer" for chicken breasts, fries, and other small meals.