I have a countertop convection oven that's nice to use when I don't need to cook a big sheet pan worth of stuff in the oven, especially in the summer when the oven heats the whole house.
convection ovens/air fryers are usually an upgrade flavor wise vs microwaves. you put in similarish amount of effort into "cooking" with them but air fryers usually will taste better at the cost it takes a bit longer. they are smaller so they dont take as long to heat up as a traditional oven, which is really standard ovens biggest weakness.
basket style air fryers imo are more convenient if youre heating something that needs to be shaken or moved around after a bit, usually a lot of fried stuff vs a convection oven that uses a tray.
They don't do anything a convection oven doesn't also do, but they're much faster and more efficient. If you just want to reheat something small or make one serving of fries, it's a waste of time and power to heat a whole convection oven.
I had one like... ten years ago? It didn't make enough of an impression on me to keep it in my moves or replace it, but it wasn't bad. If I lived in a place without an oven I might consider one again. The issue is I tend to meal prep and cook in bulk, because I'm lazy, so the low capacity can be a problem.
Though the real heads all make sure they got slow cookers