I think my power booster provides ~250lbs of assistance, which is a decent amount of force. When my booster leaked, it would cause my engine to stumble at anything under 1000rpm. It was a nice little reminder: vacuum isn't free.
My brakes would be counteracting transmission creep on the hill anyways. It might only save 0.000001 gallons, but hey...that's 0.000001 gallons for free. I'll take it.
In any case, I started using the emergency brake method on moderately long lights instead.
- LostCause