Yep, a split/multi wire circuit sort of functions like a 240 volt circuit. Basically where the neutrals tie together between the two loads, the current goes to the other circuit, and the neutral only carries the difference in load back to the breaker box.
This also happens in the main breaker box in your house and in sub panels. If the loads are exactly balanced, there theoretically would be no current traveling back to the breaker box in the neutral, so again in theory, you have less resistance from wire length. Whether this has any practical impact in a regular house or shop circuit is kind of debatable though. Myself, I don't like them because they are kind of a pain, and I have too many memories of getting zapped from current backfed from the neutral of unexpected split wire circuits in old plug fuse fuseboxes.
Note that the opposite is true if you are on the same leg of the breaker box, then the neutral would be carrying both loads, which is bad.