Short version: They now add a QR Code watermark to your downloads so you'd pay for their software

Used to be the best, now you'll notice some "downloads" are slower, that's because it's actually downloading, then adding a QR Code, frame-by-frame, to your downloaded video, because now they decided that they will add the QR Code as a watermark to get you to pay for their convertor. Don't believe me? Hop on Youtube right now and try it. It used to be a very simple downloader as is, now it's unusable. Unusable unless you pay.