Yes keyless cars are more easy to steal than cars that require keys.
With a keyless car that requires the computer chip to start it a car thief that knows how to hack things could easily make their own keyfob for the keyless car and be able to steal the car.
So they could get access to a keyfob that would fit your car and program it to start your car.
However for the common thief that steals cars they would have a harder time stealing your car by simply unlocking it and starting and driving off with it.
A car thief could also just dress up like a repo man and then use a tow truck to act like they are repossessing the car and then steal it that way.
So be careful because there have been some cars stolen by people who acted like repossession people and then stole the car or vehicle that way.