Initially it was to lay as much ink down as we could for back lit signage, which is what we bought the thing for. From there, moving into other stuff like door vinyl, I just kept it at 20 passes in order to match prints on clear. Then moving into partial wraps, I see no reason to skimp on ink for either time or material usages' sake. Since I print a handful of things a week, I'm not tying up the machine to a point that it hurts production, but I'm aware that I'm using more power to print for 8 hours compared to the 3 hours it would take at something like 8p.
Also, everything pretty much comes out perfect every time, aside from those difficult colors.
In the end, I have a printer for convenience sake and control, I make my money with my router and bucket trucks.