your wood shaft doesn't play any different with changes in the weather that is all horseshit. its not a golf club that bends with your swing. your swing is straight,
and even the old wood shafted golf clubs which i learned on didn't bend according to the weather. and if wood did that all the time, building houses would be a nightmare.
the cueball doesn't roll different because of the weather its the cloth that slows down the balls as it get more humid. i would guess because there is slightly more friction on a damper cloth.
Shafts are flexible and bend during a shot, some more and some less but they do bend and vibrate and work a bit like s spring.
Humidity and weather will affect that, might not be noticeable with all shafts but it’s there.
But that’s not the big issue.
Flying across the world for a tournament, getting your cue out and realize that the shaft has warped is not fun… finding an annoying ding in it is also not fun, finding a cue repair shop that you can trust across the world is not fun.
Non of these are issues with CF shafts.
Quiet mind when it comes to the personal equipment is golden and worth every penny and the phase it takes to get used to CF.