I still use jWowUpdater.
I noticed it doesn't "Update Addons" anymore, but it will "Reinstall Addons" just fine.
Doing the reinstall grabs whatever the latest version is and downloads it.
So, instead of updating......I just reinstall. =)
What you're doing is using a fuckton of bandwidth (depending on the number of addons you have) for no good reason. If you have 150 addons, and five have been updated in the past week, you're still downloading 150 addons. If enough people start doing this, we'll probably start seeing every addon distribution site go to registration-only and/or capcha downloads.
This is the same problem WAU had - munching bandwidth and costing insane amounts of money - except for the fact that it was restricted to files.wowace.com.
Although he can't detect the local version of an addon, but only after its been updated.
That's pretty much impossible in the case of addons which don't put the version in their TOC. I'm pretty sure WAU itself operated the same way, though it had a complete list of addons which you didn't even have installed - but that's because it had access to the central repository. :)
I can still bet my warglaive that jwow won't live long if it provides free one-time add alternative. I saw on some of the topics some user have made a script to auto-update addons from the current curseforge but decided not to post it. The administrator politely thanked for that and said that he/curse will not notice such actions if they don't become public.
Just tested JWoWUpdater - It's downloading revisions tagged as Release.
So feel free to suggest features, but remember that it might be a while before they are considered/implemented.
The "delete before install" option seems broken - old files remained when I tested. When adding addon-handling, addons which come from Curse disappear from the unhandled list immediately upon setting the address. Other sites stay in the unhandled list until I click "Accept". Also, you may want to change "Installed Date" to "Release Date" because it shows a few addons which were updated months ago to be installed months ago :)
The main question was not answered at all. If the updates are premium only, the rest of us are stuck. It doesn't matter if an updater can download from Curse, if the updates aren't available without a paid account. In that case, no, nothing other that curse client will work.
Premium gives you the big "DOWNLOAD EVERYTHING" button.
Non-premium allows downloads on an addon-per-addon basis.