Talk about a tool you genuinely love and know deeply. Explain the specific workflow improvement, not just features.
The specific tool matters less than the reasoning. Strong answers explain why the tool fits their workflow, what problems it solved, its limitations, and when they would choose something different. Look for genuine enthusiasm and depth of knowledge, not just name-dropping popular tools.
Tests depth vs breadth. A candidate who knows one tool deeply and understands its trade-offs is more valuable than one who has superficially used everything. Also reveals learning style and curiosity.