I actually think the air changes the calculation of it.

The whole point of the air is that it's thin and light.

If you put it in a thick silicone or rugged case,

you've paid for a design that you no longer really get to experience.

If it were mine, I'd probably do one of three things.

Option one, what I'd do, tempered glass screen protector.

No case.

Except that you may pick up the odd tiny mark over a couple of years,

but enjoy the phone as Apple designed it.

Option two, probably the sweet spot, tempered glass screen protector.

Ultra-thin case, 0.51mm, such as one made from aramid fibre or very thin paper.

That protects against scratches and minor marks without much fault.

It's the compromise I'd recommend.