My friend's parents dropped a shampoo bottle in their new build, and it broke through the bathtub. I hope this rough surface will be more durable.

I'm imagining some rough sandpaper layer that comes off every time you shower until it's smooth anyway. Glue is expensive, you know?

There are smoother and rougher tile surfaces. When getting tile put in my house I've made something of a point of avoiding the very slickest/smoothest tile.

I feel only rocky texture will be satisfactory after a year. Or is there any chemical that can safely strip the soaps and other fatty stuff from the mineral?

My roughest and lightest tile--which has to be replaced for other reasons after a couple decades in what we call a mudroom in New England--could probably be cleaned but would be a procedure. In general, darker and just somewhat textured tile seems to work pretty well in less-trafficked areas.

There's so much about showers in hotels that I hate a good proportion of the time: super-slick tiles, high step-in tubs, accompanied by no handholds. I've gotten more sensitive to this over time but even when I was much younger, nearly took spills a couple of times.

That's fair. It's one thing to tell people "don't build things in such a way that other people would be put at risk", and quite another to threaten people with punishment for choosing to take risks themselves.