I love the spurcycle bell I’ve got on my bike, but even though it’s very loud and I ding it like I’m blue oyster cult and someone’s got a fever, people still either ignore it or don’t register it until I’m right behind them. I do think it’s got something to do with local experience though- I grew up riding in an area where mini cowbells were available at the start of most trails (provided by local bike shops and trail orgs) and everyone knew the sound.
That's a good idea about the reason, and yeah, its personal - I like being able to move parts from frame to frame. I had thought that 30.9 was losing favor to 31.6 but I must be mistaken. I'm actually surprised that they use the same internals. I would have thought that if internal post diameters are the same, bushing sizes would have to differ, but is that not the case?