It’s not about forgetfulness, there’s no technology that can overcome that.
It’s about having technological backups to the different ways to access and start the vehicle.
I think the thought before about the key card was, “what use is this thing if you have to get it out of your wallet, hold it behind the door handle to unlock, put it in the charger to start the truck, when if you have the fob in your pocket you don’t have to fiddle with any of that”.
The key card CAN be a backup to the fob if the fob battery dies, or if you forget the fob, but its main purpose is to be a backup to the phone as key feature in case the phone dies, cellular service is bad in a particular area, or it just flat out isn’t working at the time. There has to be an emergency backup for that, and since you’re not going to carry the fob around with you when using your phone as a key, the key card is the backup.