easier to make, only has to go sideways one direction from "base" Center need to go both left and right from "base".
Most of these old ones are built to have the entire shuttle move with the needle, so that makes a big difference, once they went to moving just the needle, left/right/center was not near as big of a deal.
For most clothing construction, left homing is not that big of a deal - however I actually sew more often with my needle over to the right of center.