Yeah, crazy. No sealer will hold up to makeup and purple hair dye. And no sealer prevents etching. Hairspray will etch it. Lots of household products etch.

Yup. Crazy. Kids never keep anything nice. Consider a white porcelain hex with gray grout, a nice classic look that's similar to a marble hex. No sealer will prevent stains and etching completely, they just give you longer to clean up the offending spills. If you don't stay on top of it every second, it will get ruined.