I always cringe when I hear these touted as “safety features”. They are anything but.
It’s a nightmare scenario: in the middle of the night, your smoke alarm goes off. You wake up to a house rapidly filling with dense smoke. You crawl to the front door and try to open it, but the deadbolt is locked. The key to the deadbolt isn’t in the lock, because you didn’t want to give a burglar easy access by cracking the glass in the sidelight and reaching through to unlock the door. So the key is somewhere else… probably resting on the piece of trim directly over the door. Reaching it means standing up in the hot fumes, fumbling to find the key. If you manage to find it, you then need to get it into the lock, with your eyes watering and lungs burning. You’ve lost precious escape seconds.
All exterior doors should have single-key deadbolts, with a knob on the interior to unlock it. If the door has a glass inset, or there are glass sidelights, you can reinforce these with stronger glass to prevent break-ins. Belongings can be replaced; it is far more important to make sure the occupants of a home can get out in an emergency.
Fire code calls for egress doors that do not require “special knowledge” to operate. The location of a key qualifies as special knowledge.