Just because it works, doesn't mean it isn't stupid. You're looking at significant damage should you fail with multiple chances to do so. That saying is more for improvised solutions that just look dumb
Except something that works can be stupid by being inefficient. If I had to drive to a store that going one road is 5 minutes but going another is 20 than I would be stupid to take the second even though it still works.
Something works when it completes what it is required to do. How efficient it is in doing so is by no means a way of measuring if it works or not because no matter how inefficient something is as long as it stays above 0% it still works.