Even if you're "not too concerned", it doesn't hurt to consider your options in the tire/tube/rim/spokes department to keep the total weight reasonable. By using the DD hub, you're saving the weight of a front derailleur, extra chainrings, front shifter/cable, etc, so you don't need to resign yourself to having a heavy bike yet.

(Of course, I'm not going to twist anyone's arm to be a weight weenie. )