To add another note to this, its a bug that Apple seems to know about. I can't link to it because its marked CONFIDENTIAL across the top of the dev forums, but in short its known about and being investigated.
I suspect the reason is due to security concerns about running JIT executable code in 3rd-party apps. I have a harder time understanding full-screen web apps, however. Those should be running within some kind of full-screen Mobile Safari mode.
I would paraphrase this to "Nitro JS not enabled for fullscreen apps and UIWebView".<p>Their exact motives will be revealed when they announce whether they plan to fix it or not.<p>Sure looks like a convenient bug though. In a sense, Microsoft probably didn't intentionally loose to other browsers with IE6, it was just very convenient for them to keep the entire web application ecosystem gimped for a few releases of Office...
Does apple actively want native apps to out perform html5? Of course, but enough that would hinder the natural install points, seems a little crazy even for apple...... is this the same on the iPad and iPhone/iPod?
it's a known issue to apple, several bug reports have been filed, so let's wait and see (hope). it's pretty discouraging nevertheless.
if you want to confirm with the V8 benchmark, you can use my homescreen-enabled version (version 5) here: <a href="http://pavingways.com/test/v8-5/" rel="nofollow">http://pavingways.com/test/v8-5/</a> - numbers are around 230 in safari to only 90 as a homescreen app :(