One reason why I won't buy a Rolex....

[MILGAUSS88]

Originally Posted by Torque Time

The flute bezel was originally introduced and used to provide resistance for the watch maker to screw the watch together holding the crystal in place to create the water tight seal. It is very similar to the “coin edge” design visible and used to secure case backs in place today.

I think you have your history a little mixed up.
Rolex started with a coin edge bezel, not fluted.
They then introduced smooth bezels and milled bezels as early as the 30's.
The Datejust was introduced with a coin edge bezel in 1945.
I believe the fluted bezel was not used on the Datejust until 1956 when they first produced the Day-Date as well.
So they used a smooth bezel for 2 decades before the fluted bezel was introduced.
Which would indicate that it was only decorative by that time.