Many people strongly believe that Italian marble is very costly and then start looking for all other options. See I think everything should be compared apple to apple, Whether you opt for tiles or wooden flooring or mosaic flooring or Italian marble or anything. Every material will have its own pros and cons.
And ultimately it is your own choice to use the material or whatever the designer is suggesting. There are lots of pros in Italian marble that other options don’t have. With Italian marble you will not see bents which are common even with branded costly Tiles.
Mirror finish of Italian Marble is high luxurious & no other material can beat it. After 5 to 10 years you can get your floor re-buffed. You will get a brand new finish, this thing is not possible with other options. If the client understands all these things and he feels value for money then he can go for it.