What is the function of the smart lock button on the inside door handle?

Original HubSpot URL: https://learn.simpled.uk/hi-what-is-the-function-of-the-smart-lock-button-on-the-inside-door-handle

The button on the inside panel serves as a safety feature that prevents intruders from reaching through the mailbox or a window to open the door. In other words, it locks the door from the inside as well!