You should choose a chair mat with a smooth backing if your floor is made of a hard surface, such as laminate, hardwood, tile, or vinyl. These mats are frequently thinner and have straight edges rather than beveled (sloped) edges.
For use on hard surfaces, a chair mat should be level. Spikes would elevate the mat, making it uneven and making sitting or walking on it uncomfortable. A chair mat will provide some protection for hard surfaces like laminate and oak hardwood flooring. To prevent dirt from getting under the chair mat and the mild rolling motions from pressing against the surface, it should be kept in place or cleaned frequently.
Depending on how tough the flooring is, you might or might not need a chair mat. You might not need a chair mat if it's generally flat, like the tile seen in many government buildings, as the tiles may be strong enough to survive chair rolling without the need for further protection. A chair mat can prevent the chair from slipping in the grout or breaking a tile if the flooring has gaps.