Nobody said how much cane sugar is added. My guess is that the purpose is increased viscosity and that a quite a bit is used. It might be usedful if you want to carefully control what area is wetted by the solution.
Chemically, I can't see much purpose. But I'm not much of a chemist. Cane sugar (sucrose) is a dimeric cabohyrate. That means there are a couple of aldehyde groups and a bunch of alcoholic hydroxyls along an aliphatic carbon chain. Ho hum. I've seen it used to retard development in the first bath of a divided developer (Kodak), and it's the (weak) reducing agent in the Rochelle salt method of mirror silvering. A nice quality is that it is miscible (not quite the same as soluble) in all proportions with water, but that also makes it hard to get rid of. Other than that, I can't recall anything related.