Chrome's extensions ability is still somewhat new.
Ok, maybe that's somewhat of a lie. It has been been around for a while. But definitely not as long as FireFox. So while those extensions are not yet available (at least not all of them), that's not to say that they will not be sometime soon.
In any case, I think that it's reasonable to use Chrome for normal browsing and then switch to sluggish FireFox for any testing I need to do.