A dry tile can hide the real problem
A bathroom floor can feel perfectly normal when it is dry and still become noticeably more slippery once water, shampoo or body oils are present. That is why judging a floor only by touching it or walking on it dry does not tell the whole story.
For wet areas, the more useful question is how the surface behaves under the conditions in which people actually use it.
Soap and cleaning residue can reduce usable grip
Residue can form a thin film between footwear or bare feet and the floor. Even a textured tile can feel slick if residue is allowed to build up.
Before considering any treatment, a proper clean is important because it helps separate a contamination problem from a surface-traction problem.
Smooth finishes can become less forgiving when wet
Glossy, polished and dense tile surfaces are often easy to clean and visually attractive, but some become less forgiving when water is introduced. The exact behaviour depends on the material, finish, wear and contaminants present.
What homeowners can do
Start with cleaning and housekeeping. Keep drainage working, remove residue, and use appropriate footwear or bath mats where suitable. If the floor remains slippery, a professional anti-slip assessment can help determine whether a surface treatment is appropriate.
Anti-slip treatment should be considered one layer of risk reduction, not a promise that a floor can never become slippery.