I sometimes think they fit keyless because they can, and because other makers are doing it. I can see the advantage of not having to hunt for your keys if you have your hands full (in fact I just saw a woman with a trolley of shopping walk up to her Mercedes, and the boot opened itself electrically. Whoopie. But decadent really, and not having it is a first world problem. At least she didnt have it all delivered to her sofa. )
I dont think there is much difference between keyless and keys. If a determined thief wants your car or contents they will burgle your house for the keys, smash a window and grab something before you can react, or stage a fake 'prang' and highjack the car when you stop and get out. (They already know this

) Any distressing and dangerous consequences are going to happen anyway.
Its best not ponder on how modern life may be getting more dangerous. Highwaymen and footpads were a danger in the 18th century. And hanging didnt stop them. Take all reasonable precautions, and remember that ultimately its only a car. Maybe I only think this way because ,apart from a motorcycle stolen (and recovered) when i was about 17 -( back in the good old days when there were bobbies on the beat and everything was rosy) 'But nothing much has happened to me since. (apart from about 10 years ago when someone stole the chain off my garden gate

)