MCAS is a convenience feature that counteracts the plane's tendency to pitch up more than you want when climbing.
Nope, MCAS is required to meet the requirements set forth by the FAA. That's not a convenience thing. Various nannies may seem like convenience things in a well balanced car, but they become far more important in a powerful, poorly balanced car like a Porsche 911 or Dodge Viper — cars that have earned reputations as widowmakers.