I don’t use a Raspberry Pi ( Octoprint/Octopi/AstroBox ) to control my printer. Plus, external “stop/pause” will wait for the buffer to drain the command … by which time you have lost the print. when the filament runs out, it’s important for the print to stop immediately, and the Lulzbot must give you a good loud alert beep and go into the “change filament” mode — get off the model, move over, stepper hold ON, and let you feed new filament in or clear out the bore and re-load the filament that you were using before starting up again.
Andrew Tunell’s detector is awesome because it measures that the filament has stopped moving. This means it’s detecting filament jams, as well as filament out, and I think of it as a critical-path item that every 3D printer should have.