To be honest, I have never heard an adequate explanation for it. I wish I knew!
Unfortunately, in this hobby, much like in life, we sometimes have to resign to the fact we might never know the answer to all things...
Sometimes the explanations for why something are quite mundane. If I reflect on some of the decisions I have made in my life, there are times when I have done something (e.g. getting out of a particular
side of the bed one morning), just because I did, not because there was some underlying strategy or framework which led to me doing said activity. But to a curious alien observer they might think there is something more to it!
I do notice when we discuss coins, that we put everything under a forensic lens and in some cases, hold some things to be more significant than they actually are, but I suppose it makes it all the more interesting!
Peter