I don’t see any real advantage of the push button start. But now two out of our three cars don’t have any key. One disadvantage of push button was demonstrated recently at a trip to the airport. The fob was in my wife’s purse, I was driving. At the curb she jumped out to find our daughter that we were picking up. As she ran off the car started making some beeping noise and the outline of a key appeared on the dash. The car was still running though so I was able to park. If I had stopped the engine then I guess I would have been stuck. Odd that a key symbol is used in a keyless vehicle.