They are about the same if the horizontal application is left unblocked. But blocked, it is about 40% stronger. On a wall, it is allowed either way if the panel is thick enough for the stud spacing. For floor and roof diaphragms, the spanning of multiple members comes into play as the face grain of ply and fastener length and spacing, but not in walls, unless it is an engineered shear wall.
Most local jurisdictions require ply on the corners and every 25' of wall, as per UBC. This is to transmit the wind and seismic loads to the foundation. They require blocking at all panel edges. IRC 602.10.7
When I started building in '73, we cut let-ins at corners and 25', installed 1x4's, nailed after square, installed black board or foil face, then raised it. Installed cedar horz. siding after windows and felt. We did T-1-11 siding, 4x8, vertically. So it was no wonder that when ply started being used as sheathing for shear , we installed it vertically as well. Especially in production framing, we did not spend time putting in extra blocking as required to pass inspection, with horz. appl. Only once have I installed ply horizontally, I think it may be a local "how you learned" thing. Be safe, G