back in the era of 6 speeds the chain pin could protrude out from the side plate, now it cannot
the chain-making machine expands the pin like a rivet head and to narrow everything down to fit 11 in the space of 8
there is no margin of error with flush ends of the chain pins.

now you only can shorten the chain in whole link lengths, the 2 inner links joined by the quick link.

there is rivet making chain tools Expensive & far from fool proof to use ..