The rail stays on. Only the belts and the gantry come off. So there isn’t any more alignment than just turning it on in the morning, assuming nothing gets bent out of whack when moving it.
24V helps in only one area. More torque when going faster. It has the same torque when moving slowly, but at high speeds, 24V has more torque. “fast” and “more torque” are relative, and reasonable speeds are plenty strong for 12V. I am still a big fan of using 12V, but they cost about the same, so using 24V is not a big deal.