The switch alone does not provide security if the supply chain is compromised. I believe a malicious actor could act along this chain by setting the switch to O

The switch alone does not provide security if the supply chain is compromised. I believe a malicious actor could act along this chain by setting the switch to ON and rewriting the firmware, just like they would replace a removable chip. A step in this direction has been taken by "Server Configuration Lock" (e.g. HPE) while servers are in transit