Scot here. Only a kilt if it’s kilted – ie if it has vertical pleats at the back for freedom of movement. No-one seems to offer this in a rain skirt, but for a few grams of extra weight, some back or side pleats would produce a more functional garment than a simple wrap-around.

Turns out that a Hiking Kilt is a thing.

You can get a microfiber hiking kilt for around 330 grams, or for a few more grams you could get one from Mountain Hardwear in a technical DWR fabric!
https://www.mountainhardwear.com/mens-elkommando-utility-kilt-OM3417.html
Seems that people have thru-hiked in them – it’s a genuine option for shorts wearers, with the ultimate in ventilation. Though as someone who had to wear a kilt at school, I’d be a bit concerned about chafing my thighs at the hem.
Robert Service, who was raised in Scotland, promoted the use of the kilt in a verse that contains the following immoral lines (I’m not making this up):
Imagine how it’s braw and clean
As in the wind it flutters free;
And so conducive to hygiene
In its sublime simplicity.