It isn't more challenging, actually much less. If you look through all my posts, I've been able to more accurately recreate hundreds of characters. I am only limited in that domino mask faces in yellow all seem to have mustaches. Yellow gives me more variety. When I see characters that are POC and they use the same 4 black characters heads over and over, I'd rather just see them with a yellow head that better fits the character. Flesh color lego assumes that there are 4 skin tones, its just not even close to being accurate, yellow can represent anything and anyone. It is more in the spirit of lego. So main reason being more choice, secondary reason is philosophical, lego was just better before fleshtones, representation wasn't an issue, now it is.