...and difficult to pirate, a major reason so much software moved to the web.

On the negative side for the consumer, the software and whatever data you committed to it will disappear if the company ever decides to stop supporting it or shuts down.

Also you are pretty much forced to be online in order to use it, so if your device isn't in a wifi friendly area and/or you're trying to limit your internet usage for whatever reason (i.e. more productive with less distractions), the software is useless.

That's actually not true with cache manifests, IndexedDB and service workers. You can make an entirely fully-offline webapp that stores data locally. This is all relatively new stuff, of course.

That's true, although it tends to hide the data in some '/users/documents/appdata/local/roaming/cache' craziness rather than true i/o. I still can't load a preferences file off my ~/crazy_named_personal_folder, update it, and then save to the same location, at least as far as I know (I've only played around with local storage briefly).

And that's a lot easier to lose and a lot less portable than all the stuff I care about in a single folder that I sync with an external hard drive, a usb drive, and dropbox, automatically.

But it's still better than nothing, and I'm glad it's an option now.