This technique is called "behavioral interviewing." By asking about a time you actually did something, ideally the interviewer can get a better sense of how you do things than just asking a hypothetical - real life is complex, and they want to know how you deal with real decisions in real environments, where people disagree for good and bad reasons, where the best technical option isn't always the feasible business option...
The best answer to a question like this does showcase your success, but also goes into details about how you overcame issues and conflict (ideally without coming across like a rabid wolverine).
There are plenty of people whose examples provide a questionable thought process - "I wanted to use it because it was new even though it might not have been a good fit/I wanted to use it even though it was old because I'm familiar with it", "I just went ahead and did it even though others objected because screw them/I gave in to what the lead wanted because who cares anyway"...
You want to project confidence, but confidence that is warranted because you understood the technical and organizational impacts of that choice, you can successfully negotiate technical decisions with others, and you can show good judgement and select implementations that will be successful.