Lightroom Downloader - Incremental

From what I can see whe I test the Downloader, it IS incremental, although it doesn't appear to be when it runs again after the first run, i.e. it appears to be downloading everything again, but actually only downloads any new files since the last run.

Personally, I find the Downloader to be somewhat buggy (or it just doesn't work the way I expected it to work), so I certainly wouldn't depend on it as backup of the cloud-based photos. For one thing, album membership info is not retained in the downloaded files, and there seems to be some inconsistency in the way that proprietary raw files are downloaded....for some raw files an xmp sidecar is also downloaded, as expected, but for others that's not happening. 

The Downloader app is really designed as a "lifeboat" for those users who are exiting the Lightroom subscription, or for those dealing with the estate of a deceased user (so album membership data might be immaterial), and not really intended as a pure backup of the cloud images. Exporting images as original would be better, though that still wouldn't get around the issue of the lost album membership.