Personally not a fan of the push button, but people are of course free to do what they want. I figure if I'm going to have house keys that are probably on the same ring as the car fob, what's the big deal about using the key rather than a button to start the car?
Two stories (for information only, and no emotion from me; just don't understand why people take such risks for so little convenience):
I was walking in a parking lot once where a woman flagged me down because she didn't know how to re-start her car. For some reason, there was a need to reset something before pushing the button again. I wasn't familiar with her car, but we tried 2 or 3 things to 'reset' before it started.
There's also the story of people who start their car with the button, go back into the house for some reason and manage to leave the fob there. They arrive at their destination, turn off the car and then are stuck until the fob is brought back to the car.