While that certainly explains why they might use a microcontroller, it's certainly not necessary. The lock can be connected to a simple switch used for signalli

While that certainly explains why they might use a microcontroller, it's certainly not necessary. The lock can be connected to a simple switch used for signalling occupancy, same as any security or commercial fire protection system. Auto-closing and auto-opening are akin to an automatic door, which operates just fine as a regular door, but has a fairly dumb motor attached for accessibility. Perhaps the microcontroller solution ended up being cheaper - but based on this (particularly going to out of order after such a trivial "hack"), the mechanical solution is far more robust, because at worst you can still operate the door manually.