And players should be allowed to talk smack, cough and belch while their opponent is in the act of hitting the ball. Fans should be encouraged to cheer or boo and hold up signs.
I think it all depends on the pace of the ball. A well hit putt and it won't matter really but if it is a little fast I think the stick will kick it out more times than it will allow it to drop. If it is windy then I'd say no one will leave it in, no one with any damn sense. I think the only real advantage is visual, a lot easier to see the hole from distance but they can always have it tended in this instance. I doubt that many will turn to putting with it in. Mainly just to take the other side of Chamblis
Pace of play would be my guess. Personally I've never really cared about rules like that. I've hit and made putts with the flag in, usually because I didn't want to walk over and take it out.
Pace of play is the reason they decided to allow it, but the study mentioned demonstrated that statistically you do better with flag in. You’re right, individually, it may vary putt to putt, may be impacted by distance, etc, but the study showed that across players and distances, a higher percentage of putts went in with flag in hole.