Most houses don't have an external mailbox, the mail goes through the front door and into a basket. A lot of houses on terraced streets have no front garden and open directly onto the road, especially in cities.
There is doorstep letter and parcel collection for less than a dollar.
And what happens when I don't have any signal? Writing an offline-first mobile website is INCREDIBLY hard. Where are you going to store the data? How are you going to detect the network connectivity without polling and hosing the battery because the radio doesn't timeout? Geo-fencing events?
There is doorstep letter and parcel collection for less than a dollar.
https://send.royalmail.com/