to ask what is the point of an air fryer?

[SnippedYerBarbour]

I've had an air fryer for a few months and I really think I must be doing something wrong because I don't see the point of it.

I've used it a few times to heat up frozen food, just to get the hang of how it works. Despite following all the instructions carefully, including batch size, I'm finding that things take up to four times as long to heat up as I'm told they should. And nothing's actually crispy, just warmed up.

What am I doing wrong? Or should I charity shop it?

A friend had a similar issue and was boxing it up to return the shop as faulty and that was then she discovered that she hadn't taken out a piece of cardboard before using it. I think it was between the heating plate and bowl/basket thing?? Just mentioning it in case it saves you some

How do you know how long to cook things for? If something takes 30 in the oven on 180, how long would the air fryer take?