HardieBacker Board vs NoMorePly installation

[djkprojects]

Hello,

I'm planning on tiling my first floor bathroom floor and looking at the backerboards to overboard the current T&G floorboards. I'm thinking between HardieBacker and NoMorePly however a bit confused as to why Hardie boards have to be bonded to the floor by using non-flexible tile adhesive whereas NoMorePly are glued with their own special glue ? My assumption was that these are really similar things so the application would be the same. Any ideas why the difference ?

Thanks

[kingnewport]

Just use 9mm play a screw I'd down every 4"
Old skool all day

[All The Gear]

The tile adhesive will take out any slight undulations on the existing floor and make the cement board more stable.

I hardly ever use ply these days. And 9mm isn't anywhere near good enough.