Automotive ignitions barring a few stupid setups in the 90s like the Jeep XJ (which was laughably easy to steal, but it was Chrysler and AMC so you can just expect certain levels of incompetence and shit design) have been much more than just a simple cut key. Going back to even the 80s, GM had a mostly excellent simple theft deterrent in the keys (a special resistor whose value the ECM knew, called passkeys) that made it harder than just brute forcing the ignition cylinder. It honestly made stealing someone's thirdgen or corvette a lot harder. Keys with things like fobs have evolved since and on a car with a real key made since the vast majority of this sites userbase was probably born is going to take some real specific smarts and work if you need both a physical key and whatever additional security the manufacturer has cooked into the fob. You really need an immobilizer system that requires both a transponder and a correct cut key for the security on the car to be decent.

> Adding in a stick of metal that can be trivially bypassed does nothing to make the car more secure.

Everyone can use a flipper zero to unlock a car. Not everyone can hotwire a car. Keyless ignition means criminals have a vastly larger recruitment pool of people they can offer money to do something stupid (like stealing a car for them).