Nowdays in Korea, Stars money on contract is skyrocketing.
So sometimes using foreign model is cheaper than Korean big star.
As an example, Baskin Robbins used hollywood star Drew Barrymore.
Because Korean big stars are more expensive.
I have nothing to say on the question such as ' why they use Korean top model or star. they are rich?'
In Korea the fact is recognition of fashion model is low to the masses.