Chilly, you've been given many reasons, you just choose to reject them. You keep stating that there are other responses that could be done. You've mentioned "drop the weights" many times.
When you work on your car, do you only use a hammer?
Can't get the bolt loose? Use a hammer!
Can't open the window? Use a hammer!
Have a flat tire? Use a hammer!
Mother-in-law keeps telling you what your doing wrong in your driving? Use a hammer!
(Ok, maybe the last one is appropriate
)
The point is, I like to have a variety of tools to use. If I have a freeflow at depth, yes, I WILL be going on an air-share. But I will ALSO be turning off my air to preserve it
in case it is needed before we hit the surface. The goal here is to preserve the air the team has available.
Also, sometimes a problem can be fixed (not just mitigated) by turning off the valve. An unseated o-ring requires the pressure to be removed and can then be fixed. So even a simple off-on can mean the difference between aborting the dive and doing the dive. This is more of a convenience than an emergency, but it still applies.
I a bit hungry now. I'm going to go use a hammer.
Later.