If you're a casual Evernote user, then this feature would not apply to you. As stated above, it's an optional feature, already being worked on by Evernote which I recently confirmed with Support. You don't have to use it based on your workflow. It's as simple as turning it off and on based on your needs. Someone dealing with hundreds or thousands of PDFs per month would find use for something like this. Someone who works with less than 100 PDFs a month, probably not. If you have hundreds or thousands of PDFs in a folder that you're uploading, I don't want to have to double-check every PDF in the folder to make sure it got uploaded correctly into Evernote. Evernote has the capability to check to see if the PDF is uploaded, if it is, it deletes the corresponding PDF from the folder. Simple as that.