[ericswpark]

The one advantage that air fryers have over standard convection ovens (IMHO) is that you can make smaller portions, and because these products are designed to cook small portions they can direct a ton of heat at the food, cooking it very quickly. Prepackaged meals' instructions usually mirror my experience as well, saying that cooking in an air fryer will require less cook time compared to an oven, and a drastically lower temperature as the heating element is literally right next to the food as the air circulates the heat.

Otherwise, if you already have a convection oven and don't mind waiting a bit longer, I don't see a good reason for purchasing an air fryer (other than the aforementioned advantage).