They aren't as essential for desktop browsers (now), since the relative resource constraints on a given tab are so much smaller, but just as relevant as "deskto

They aren't as essential for desktop browsers (now), since the relative resource constraints on a given tab are so much smaller, but just as relevant as "desktop" runtimes scale down in power/up in efficiency demands, and as the apps run within them scale up in resource demands. Just look to how much RAM your 25 browser tabs burn, and how warm a single tab with Flash ads can keep your MacBook Air.