That applies over a network. It doesn't apply to someone that has physical access to the machine. Even if the machine delays a response, the power profile of th

That applies over a network. It doesn't apply to someone that has physical access to the machine. Even if the machine delays a response, the power profile of the computation will tell the exact timing of the computation. Since there is lots of cryptography used to keep users out of their own hardware (or stolen hardware) these days, this is important.