I was kinda disappointed that Pokemon Sword and Shield didn't have any kilts as a clothing option. As for the tartan, that's supposed to be the Oliphant tartan (I picked a random tartan), but I'm not good at drawing tartan, so it looks kinda wonky.
You said it. It is a missed opportunity to have a kilt. It is also a missed opportunity to have a pokemon based on actual steampunk, actual robots, clocks, playing cards, chess pieces, knights, court jesters and the royal family such as kings, queens, knights, princes/princesses.