on rock, you need 70m worth of gear, on ice maybe, maybe one extra scew so it seems really good for ice. 60m...70m rope management sucks just the same. It pretty much makes it feasable to TR, or link 35m or under pitches which there are a lot. you got 10m extra. It's really nice to have more leeway as to how far you can climb and where you can put your belays. I own a 70m 9.4 and use friends 70m 9.1's.
I think it greatly improve speed in the alpine rock/ice and the ice, ESPECIALLY routes where there are no obvious belay spots whether the route be very ledgy, or super steep. It comes in handy on those "last" short pitches too cuz you can skip em.
I've climbed on many routes where it's come in very hands. Polar circus is a good example with the 65m curtains near the top.
On raps, if there are lots of anchor stations, or on a desccent with no stations, you get less raps w/one rope too.