The difference is where forces are applied and the resulting torques. But since the carriage is mounted on a rigid linear guide and beam, it's not going to affect the position in any way that matters, so... meh.
If you really want to get picky about it, the tension on all the belts being on one side of the guide rail will be trying to force the rail to bend. I built a corexy sand table with 45 x 45 mm t-slot used for the frame and as Y axis guide rails (about 1.8m long). The belt tension caused the beams to bow outward.
Ultra MegaMax Dominator 3D printer: [
drmrehorst.blogspot.com]