>>21577914 (OP)
Air fryers are very good at reheating junk food to be crispy, so like french fries, chicken nuggets, or pizza. Even though alone it will do it faster than a conventional oven or toaster oven (even with convection), you might be saving like 5-15 minutes only, with the toaster oven being faster than conventional since the latter needs longer to get to higher temps.
It's a tool that specializes well in what it does, but isn't the best at a lot of other things like toasting bread or baking, though tinkering with the settings will definitely get you closer (but that requires thought and effort which many hate doing).
I personally am fine with just microwaving to get the whole food hot the fastest, then using a toaster oven to crisp the outside. Having those metal basket trays helps prevent soggy bottom if you got it