12 seconds down to 9 seconds is not negligible. What is negligible is 12 down to 11.999 seconds because you prematurely optimized.
And even for "normal" users, shaving milliseconds matter. The general idea is that a UI should respond within 100ms to feel instantaneous. More than 1s and you interrupt the flow of thought. According to Google research, increasing page load time from 1s to 3s increases bounce rate by 32%.
Performance matters, a lot. I am not living in the UK, but if I was, I would be happy to pay taxes that make government websites 25% faster.
And even without the performance benefits, I consider removing dependencies a good thing. jQuery was great in the IE6 days, but now that even 10 year old browsers have decent JS, it is not as important as it once was. Modern versions of jQuery don't even support IE6 anymore.
And even for "normal" users, shaving milliseconds matter. The general idea is that a UI should respond within 100ms to feel instantaneous. More than 1s and you interrupt the flow of thought. According to Google research, increasing page load time from 1s to 3s increases bounce rate by 32%.
Performance matters, a lot. I am not living in the UK, but if I was, I would be happy to pay taxes that make government websites 25% faster.
And even without the performance benefits, I consider removing dependencies a good thing. jQuery was great in the IE6 days, but now that even 10 year old browsers have decent JS, it is not as important as it once was. Modern versions of jQuery don't even support IE6 anymore.