If you're on the receiving end of the code, you'll get email that explains just what kind of access (PIN code, August mobile app or both) you'll have for your visit.

This makes the most sense for regular Airbnb hosts, but it's still important for home rentals at large. Right now, the expectations for these services tend to vary wildly from host to host. Technology like this is not only more convenient, but might create a more consistent experience where you're not quite so worried about basics like getting inside.

Update: To clarify, the update from August has enabled the company's Smart Keypad to work with its automatically-generated codes for Airbnb guests. Previously, guests would have to download the August app to gain entry, but this update takes away that additional step. August has been providing that feature with its other products for a while now, and the Smart Keypad is the latest to get this update.