Pre-manifest V3, when OnBeforeRequest actually blocked requests before they were downloaded, browsing typical sites with it enabled was objectively faster than with it off. Any overhead was pretty quickly recovered in not downloading the ads.
Many benchmarks proved that. Here's one: https://whatsoftware.com/10-ad-blocking-extensions-tested-fo...
So, unless you're browsing exclusively all ad-free sites, it very much DOES matter, or used to.
Pre-manifest V3, when OnBeforeRequest actually blocked requests before they were downloaded, browsing typical sites with it enabled was objectively faster than with it off. Any overhead was pretty quickly recovered in not downloading the ads.
Many benchmarks proved that. Here's one: https://whatsoftware.com/10-ad-blocking-extensions-tested-fo...
So, unless you're browsing exclusively all ad-free sites, it very much DOES matter, or used to.