Car repair does not make car faster, nor more comfortable.
Well, sometimes it can. An engine or transmission in poor condition can slow down a car's uphill performance. A broken heater will make a car less comfortable in the winter. Repairs will correct these problems.
And so it goes with software refactoring. Removing redundant calculations and data-reads (e.g., out of loops) where possible will improve performance. Changing names of variables, functions, classes, etc., to reflect their use more closely will improve readability (or "comfort" if you will.)
Good car analogy, though.