I'd say yes- most definitely. And even a small gain in performance will improve a website's effectiveness. This will be especially true for people on a marginal web connection (such as a challenged public wi-fi.)
Along these lines, Google just published a blog article called Speed Matter [googleresearch.blogspot.com] that discusses some recent testing they did:
a daily impact of 0.5% is of real consequence at the scale of Google web search, or indeed at the scale of most Internet sites. Because the cost of slower performance increases over time and persists, we encourage site designers to think twice about adding a feature that hurts performance if the benefit of the feature is unproven.