Hi, My understanding is that it isn't legal in Melbourne ... depends on if you need approval etc. That said I have seen some nice bathrooms wth wooden floors. I'm sure they would be right if you were aware you needed to keep them dry, however if water kept creeping into corners etc you could end up with some issues.
I think it woul be hard to remove the tiles and restore the floors.
Not sure about what clear grip coating are out there but I'm sure they exist if you really want it.