Don't you get kicked out of the UL camp for using hydro discs, that is not the light option.

Part of the issue is why do people run discs, other than that they are habituated, on touring bikes. It isn't the same reason as MTBs, say mud (Mud isn't UL either). The only reason I can think of would be wet weather. Not sure the supplemental advantages of hydro are all that pressing for that, though I imagine hydro will blow mechanicals out of the water in time. Nobody worries that much about them on all the other vehicles.

Modulation doesn't seem all that big a deal on a touring bike, I'm just running wide open most of the time, not dogging cars, or racing in a pack.