[sc_rufctr]

I don't actually know but Porcelain would be easier to keep clean than a coated fiberglass.
Also... They are stainless steel in prisons and aircraft. That's about safety though.

I guess traditionally they've always been porcelain so people are used to that.

Baths are often coated fiberglass now were they used to be steel coated in enamel. What's better in the long run?