RFID door lock with an arduino

Been looking at door locks again, stumbled across some interesting projects.  This one an arduino based door lock that releases the door “latch” to unlock it.  So the manual lock can still work.  Not so sure I like the “latch” thought.  It looks flimsy and I wonder if it always needs to be “on” to be locked.  I do like how the author is just using the chip and not a full $35 uno.

http://www.instructables.com/id/Arduino-RFID-Door-Lock/