I was not referring to your comment per se, but indeed your comment fits the general sentiment I was referring to.

And I think that localStorage is indeed literally no better than server-side storage. Whether it is any worse depends on the situation - but better it is not.

"This ignores the scenario of app deployment models like Chrome Packaged Apps, in which the JavaScript code gets downloaded up-front and then is only used locally. Since you don't re-download the code every time, you only depend on the security of the code once, up-front, instead of on a continuous basis. You aren't affected by server compromise (well, no more than compromise of your OS vendor, but surely you aren't arguing that we might as well send all our keys to Microsoft, Apple, and Canonical)."

It's true that you do not re-download the code every time. Still, the trustworthiness of the code you received initially depends on the trustworthiness of the server you received it from.

So you say, "but what if I have reason to trust it initially and not later on?", e.g. when the government comes knocking.

Well, there are two things to keep in mind in that case:

a) you download other stuff with your browser. Stuff that can influence the environment where your secure and trusted packaged app runs in. See also comment of zimbatm - even if it is not formally meant to be that way, in practice there are bound to be ways around any limitations - sandboxing in browsers is still nowhere near perfect unfortunately. Server security is not entirely peachy either, but at least on a properly secured server only a limited, carefully screened set of applications is allowed to run which makes things hell of a lot easier.

b) Chrome packaged apps support auto-updating, so unless you take steps to prevent that from happening, you're never sure you're running the same version today as you did yesterday. Again, trusting the server to serve you a trustworthy version of the app repeatedly. And if you're trusting the server already, local storage is no better than server side storage.

So I guess you could say local storage is better than server side storage (for some definition of better) if you run one and only one packaged application ever in a specific installed browser in an isolated environment. The browser + locally installed web app then effectively becomes a natively installed application without an Internet dependency. More secure indeed, but kind of defeating the purpose of that whole web thing ;-)