Cause it’s prone to failure? America tried the weak federal system where everyone had a different bank and different rules. It was essentially 13 independent smaller “states” than one nation.

Even now people are aghast when Texas limits abortion or tries to outlaw gay marriage or when California’s increased fuel standards affect the entire nation.

Additionally, it makes it impossible for states which would enact stronger gun control measures to enforce them when neighbor states just hand guns out in much less stringent manners.

It also has federal ramifications when gerrymandered districts affect the makeup of our federal law making bodies and increasingly populate them with far more right or left wing representatives than would occur in more balanced districts while disenfranchising voters who’re American systems.

I’m more on the side of California at the end of the day but we’re all Americans here in America, not Texans, Californians, or Iowans. It’s fine to have cultural differences (its what makes the country beautiful in a lot of ways), but the idea we should all just “figure it out with our neighbors” who’re our neighbors cause of relatively arbitrary lines drawn sometimes hundreds of years is a bit crazy and a gift to those who’d see a weak America.