Grumpy:
it's important for maximum angle of climb in a twin engine machine that's suddenly lost one in the hover - currently there is no way to show airspeed repeatedly below 40 knots, and for many twins, that gives away a lot of performance in an engine failure situation.
It's also important for limitations such as side and rear wind at night. Like many other things, we've survived (sort of ) without it, but once we have it, we like it.