Reeving sheet for self-tacking jib

[Auspicious]

A friend recently took delivery on a Hanse 400e with a self-tacking 100% jib. The jib sheet has a 3:1 purchase to a car on a curved track. From the car the sheet goes nearly straight up to a sheave about 1/3 up the mast then down the mast to a turning block and line organizers back to the cockpit.

Question: why is the sheet routed so high up the mast? Why not directly back from the car? Is it entirely due to maintaining a fair lead regardless of the position of the car on the track?

[Brion Toss]

Hello,
This would have made a great Puzzler --- and maybe someday it will --- but for now I'll say yes, the lead acts to remove unwanted lateral effect from the sheet. Imagine, by contrast, that the sheet led to a block on the face of the mast, but directly aft of the traveler. In this position, it would always be pulling the clew inboard unless the boom happened to be amidships. The same thing is traditionally accomplished by leading the sheet forward to the base of the stay, then aft.
Fair leads,
Brion Toss