I've seen videos of this being done. how does this last in the long run? laminate tiles can be painted over too? 

Does this work on bathrooms? 

Was thinking about this too, one of my neighbours did an anti-slip coating over HDB's bathroom and kitchen tiles. 

After some research, i think pros are that (1) it's cheaper than overlaying on top of existing tiles, and (2) you won't face the issue of the tiles popping out due to the water seepage or the tiles beneath buckling (if they're older than the tiles on top).

Cons are that the coating/paint will wear off over time and you would have to touch up.

If anyone has quotes for that would be interested!