David Hicks wrote:

The whole point of a floating floor is to allow for expansion and
contraction of the timber. timber floors will expand / contract about 2mm
per metre, ( in UK weather, may be more in more variable climes ) so with a
modest room of say 4m length of board an 8mm expansion is to be accomodated.
This can not be done by nailing the boards down and will result in the
boards lifting / twisting.

The creaking noise normally stops after a while, once the floor is " bedded
in"

It depends a lot on how closely the climate is controlled in the house, too..
But normal T&G wood flooring is nailed. The boards are put down with
just enough space between them to allow for seasonal expansion. I suspect
that the point of the "start like a floating floor" suggestion is that it gives
the wood (which probably was milled, partially kiln-dried, stored outside,
and then shipped) a chance to get to something near its expeted moisture-content

in place, so the it wont shrink after being nailed down and leave 1/8" cracks
between every board. Personally, I'd be a little hesitant to drive flooring
nails over a subfloor heating system, anyway.