this method is not as 'skill demanding' as some people are making out. any decent modern tiler could crack this in 2 weeks. tiling walls in sand and cement would take a little bit longer but floor tiling is not difficult.
what is apparent reading this thread is, some people still can't rely on their own personal experience and understanding when it comes to setting times, adhesives admixes and bonding agents.
if i said, would sand and cement stick to a glass wall, pretty much all of you would say no, it would not be able to stick/bond/adhere. you would all agree that we would have to add something really sticky or to the glass and the mix? so use that same rationale when in comes to a porcelain tiles, dense concrete, bitumen or anything else that doesn't allow the penetration of water in a controlled period of time..
i'm honestly not patronising here, i understand that people can get a bit over awed when old schoolers come on and talk about the 'old ways of the force ;0) lol listen, trust me, learn and understand your setting times and adhesion and do a bit of floor levelling with a few bags of wet sand and a level and you will be so confident, you'll wonder what all the fuss was about (once again, sand and cement wall tiling is a bit more time consuming and a bit more tricky because you have got gravity working against you that's all.