I rent a lot of cars in Europe when I travel, and most have start/stop. Thankfully, most have a button to turn it off. It's extremely irritating in a gas-only car. You hit the gas pedal and nothing happens, then the engine turns over and you start moving finally. It's really obnoxious.
I think that is what the OP thinks the Niro does, too. My recommendation would be to take a test drive in one, you'll be pleasantly surprised by the instant throttle response from a stop. It's actually better than most gas-only cars, because electric motors have instant torque available. If you hit the gas pedals at the same exact time, my Niro is probably faster than my 500hp Audi with Quattro and a 5.2L V10, for the first 10 or 20 feet.
I think the instant torque availability from the electric motor is really underrated, you really have to do a test drive to see what I mean.