It's indeed, baffling, ignoring health consequences: Get fashionably darker skin now: Make your skin look (reasonably universally) irreversibly uglier/older gradually over time. This is perhaps the most controllable way to affect how old you look.

It becomes unmissable once someone is in their 30s: Some still have youthful skin, while others are wrinkly, splotched, and saggy.

I often see women in their mid 20s looking like 35 simply because of the skin.