Hard Shell/Keyboard Cover on MacBook Air M2

The hard shell cases are made of plastic. Plastic is a very good heat insulator. The M2 MacBook Air has no fan to cool the internals and uses its metal case to get rid of the internal heat.

With that said, putting a hard shell case on an M2 MacBook Air is like putting an overcoat on it and trapping the heat inside therefore causing it to run hotter, which is not a good thing. So, do not use a hard shell case!!!

Here is what Apple says about using a keyboard cover.

Using a camera cover, palm rest, or keyboard cover on a Mac notebook - Apple Support

I personally don't have a case on mine; they are build well, out of tough aluminium. If they do get scratched, so be it, they are machines that we use regularly - they're bound to get scratched eventually. I'm not sure about causing damage to hinges overtime, but if in doubt then perhaps it's best not to.