Jib tracks: An (old) alternative?

Check out the jib "tracks" on this photo (some 40ft euro racer class). I 've seen this done on some old IOR boats. I 've been assuming that the idea had been out-evolved by the standard jib track/car setup we all seem to use today.
Yet those euro-racers seem to be going back to it. Why??



Gives you infinite adjustments. The only difference is that
on Cal 20's the jibs are double sheeted.