Does additional thermal runaway in OctoPrint add anything and shouldn't it use a smart plug to kill power instead?

Question

With the following thought in mind: 'Two eyes are better than one' does additional Thermal Runaway detection in OctoPrint add any benefit?

This OctoPrint-ThermalRunaway Plugin seems to add a basic ThermalRunaway detection in OctoPrint. I understand all the smart disclaimers he makes. Security-wise, of course, we should prefer mechanical over firmware, and firmware over external software (OctoPrint). And I think printers that don't have at least any kind of firmware runaway protection should be trashed instantly.

However, assuming you already have a printer running firmware runaway protection would this OctoPlugin add any value, 'in case firmware runaway protection' somehow fails?

Related: Firmware runaway detection as well as the mentioned 'solution' in OctoPrint are based on sending an emergency gcode to the board and performing an emergency shutdown.

Wouldn't it be better, more secure if the power was cut from the printer entirely? Eg. instead of an OctoPrint plugin sending an emergency g-code, it sending an power disable command to a smart plug (API)?
_{Source: Octoprint-ThermalRunaway issue}

Answer 1

It can save prints in specific situations. If you set maximum temperature lower than the one configured in the firmware, and configure the command set to cause printer to stop heating instead of stopping altogether, it is possible that plugin will stop printer from overheating before printer will panic and stop mid-print.

This, of course, does not replace other protections, but I recently lost a couple of hours of printing due to stupid error on my part, and this plugin might have prevented it.

It shouldn't be used instead of firmware protection. But I can see how it can be use to supplement it.