There seems to be a huge overlap in functionality. But a major difference is that Paperwork is a local application that runs on Windows and Linux, while Paperless has a web front end that makes it accessible anywhere (it also has some independently native apps for mobile).
Everything runs locally, OCR, ML, etc, which can be a bit taxing on lower end hardware, but there are ways to disable the more advanced and computationally expensive features, like NLTK for advanced Natural Language processing.
https://docs.paperless-ngx.com/