Fortnite doesn't have lootboxes. The Save The World mode did but they recently removed them so you always know what you are buying if you decide to spend money.

I'd say it's not pay-to-win either because most of the skins people buy in the shop are more flashy and easier to spot than the dreaded default skins.

I think this is less about Fortnite and more about people finding another way others are different and using it as a lever to make themselves feel better about their own insecurities.