Even if you do benchmark something, maintainability can be more important than a marginal performance improvement.
I've seen this happen a lot with JavaScript, particularly in the last 5-10 years as JS engines have developed increasingly sophisticated approaches to performance. Today's optimization can be tomorrow's de-optimization. Even given an unchanging landscape of compiler/interpreter, tightly-optimized code can become de-optimized when updated and extended, as compared to maintainable code that may not suffer much performance degradation upon extension.
I've seen this happen a lot with JavaScript, particularly in the last 5-10 years as JS engines have developed increasingly sophisticated approaches to performance. Today's optimization can be tomorrow's de-optimization. Even given an unchanging landscape of compiler/interpreter, tightly-optimized code can become de-optimized when updated and extended, as compared to maintainable code that may not suffer much performance degradation upon extension.