It would work. I framed in a custom shower stall with hardie backer(basically cement board) with a bench and tiled it. Works great. No cracks in the grout. Of course the bench isn't getting the same use as a kitchen floor, but it's 3/8" thick and holds my fat ass up when I'm too tired to stand in the shower
Cement board screwed down to a a solid subfloor, then pennies glued down with a poly finish...I think it would hold up (based on my experience with pennies, cement board, tile, and glue--I still have a penny glued to my garage floor from the vanity project and that fucker is not at all interested in coming up).
I also think it would look stupid.