Cement board vs ply wood

[asalcedo]

I am renovating the entrance hall floor at home.

I am removing the old tiles and laying new ones.

The old tiles are glued on 18mm plywood.

Most likely I will have to remove the old ply, to expose the floorboards.

I have been told that cement board like

'Hardiebacker 500 Cement Board - 12mm | Topps Tiles'

stronger, certainly more water resistant, and overall preferable to ply

Water resistance is not an issue in my case, no leaks are likely in the area.

I do like the idea that it is thinner, and since I am going to lay Ditra matting, which is about 5mm glue included, the overall thickness will be very similar to what I have at the moment, which is preferable to match the level of adjacent rooms.

Cost aside (which is not that significant in my case, given the area), can the cement board be used on top of the floorboards without ply underneath?

If yes, is the cement board preferable to ply in my case?

Thanks,

Antonio