A machine that is 99% idle isn't running at 1% utilization all the time. It's idling 99% of the time and running flat out 1% of the time. The user pushes at least one core to the limit with every action they take, even if only for microseconds.
This is why performance matters even with a machine that is mostly idle. A faster system will respond faster to events. It will have lower latency when communicating over a network. It will handle user inputs faster. Users will complain that a program takes a second to respond even if the load average is 0.01.
(I know CPUs enter lower-performance states when lightly loaded. They can go from idle to their highest performance state in much less time than it takes for the user to notice latency.)
This is why performance matters even with a machine that is mostly idle. A faster system will respond faster to events. It will have lower latency when communicating over a network. It will handle user inputs faster. Users will complain that a program takes a second to respond even if the load average is 0.01.
(I know CPUs enter lower-performance states when lightly loaded. They can go from idle to their highest performance state in much less time than it takes for the user to notice latency.)