Has anyone checked this out? I guess it's basically just like VT Uploader both now inside the browser?
Yes, I use it since many years, mainly for scanning URLs, very convenient. I haven't used the new VT Augment functionality. By the way, since VT4Browsers version 4.0, there were three updates, latest is version 4.0.3. In version 4.0.2 a bug was fixed, when opening an image in Firefox (on Kubuntu 20.04), and choosing to print, not only the image was printed but also a VT icon and some text. I don't know what else was fixed in the three updates, there were no new release notes.
Oh OK, I don't really need site scanning. But for automatically scanning downloaded files it might come in handy. On the other hand, VT Uploader works just fine. But this one seems to have a couple of more features like you mentioned.