> A managed switch will allow you to power on/off specific ports.

As somebody that's looked into this... yes, but. The contemporary light switch is instant. Within a few nanoseconds of your brain feeling the "click", you see the light. There's a noticeable latency from an API request to the switch's control plane which then talks to the power control which then turns power to the port off and then the light goes out. You have the additional delay of poe negotiation for the "turn on" operation, too.