Yesterday Amazon announced a new API that skill developers can now take advantage of, the device address API. Up until now if you needed to know the locality of the user you would be required to prompt the user to tell you (of course making sure you made use of the appropriate locality slots).
With the addition of the device address API you can now request permission from the user to obtain location information from Amazon directly. At present skill developer can request either the full address or a more watered down location of Country and Post Code. The permission can be granted at any time, for example if you have enabled the API in your skill the user will be presented with a list of permissions that have been requested in a similar manner that users are already accustomed too with Android apps for example. If the user already has the skill enabled prior to activating the API of course you may need to prompt them to grant the permissions. This can be done with the new AskForPermissionsConsent card.
As the announcement states there are other scenarios the AskForPermissionsConsent would be required, for example users are not prompted for the permissions if the skill is enabled using their voice directly on the Echo.
Apart from account linking this is the first time Alexa skills have had the concept of permissions. Clearly the AskForPermissionsConsent has been implemented in a fashion that seems to indicate that Amazon will be introducing further available permissions in future.
The address that is given from the API is the physical address that the user manually entered into the companion Alexa app therefore I would not necessarily trust this information for any important tasks. I would suspect that Amazon will extend the API at some point in the future to be a bit more robust and provide geographical coordinates for mobile device utilizing Alexa such as the recently updated Huawei Mate 9. The registered location for mobile devices such as the Huawei phone or even the Ford series of cars that will utilize Alexa the registered location is less of a benefit than the real location.