“Aesthetic” is widely used in the US as well. When I (a US person) see “esthetic” used in this way, it looks like a mistake to me—I associate that spelling with

“Aesthetic” is widely used in the US as well. When I (a US person) see “esthetic” used in this way, it looks like a mistake to me—I associate that spelling with the cosmetics/beauty industry (i.e., "estheticians").