The exact same power outage, at the exact same door, produces two opposite hardware behaviors on purpose — and which one is correct is a life-safety code question, not a general security preference.
This is specifically about what an electrified door lock does when power drops — not a generic IT-systems "fail open vs. fail closed" framing, but the actual hardware behavior wired into a real door. A fail-safe electric lock unlocks the instant it loses power, because that door sits on a required means-of-egress path and people must never be trapped behind it during a power failure or a fire. A fail-secure electric lock does the opposite — it stays lockedwhen power drops, because that door protects something where uncontrolled access during an outage is itself the bigger risk, and the building has another compliant way out that doesn't run through it. Neither behavior is inherently "more secure." The building's egress requirements decide which one a given door is required to use.