Early Central European guns tended to Shorter barrels. West Europe saw more longer barrels.
Some Central European rifles would have long barrels, most were closer to 30” range.
European gun makers made some of the early American rifles with shorter barrels then west Europe tended to produce.
Most of the customers for American rifles were from west Europe and tended to think in long gun size.
Longer barrels will give a little more velocity in a given load.
Longer barrels give a longer sighting raids so it makes it easier to aim well
Maybe those things were the reason, I think it was style.
Sometimes something becomes popular then after the fact people invent reasons why.