Do new cars need a tachometer?

For years I have thought how wasteful the car vehicle makers are when they include a rev counter in every vehicle. I have asked several friends including lots of women and they do not have a clue why this instrument is there. Also, for the layman it means nothing. What does it matter to me if I’m doing 4320rpm when I change down or brake into a corner? Most vehicles in Australia are autos and rev counters are window dressing or bling as we say. A useless waste of money. I challenge you to ask all your non-car mates and friends what they perceive the rev counter does for their driving. I'll guarantee you get lots of "I don’t knows". Surely there’s a saving there.