I can maybe see some value for opening a web page like this, then taking a set of screenshots (for me CMD+SHIFT+4) which automatically get added to the web page, which the user can then curate in some way to generate a final image for download. If the dev who built this web page can work out a way to get the web page to automatically ingest user screenshots while the page is open then I think this tool becomes a lot more interesting.

I did a similar thing for generating a video from multiple screen captures - GitHub repo here: https://github.com/KaliedaRik/sc-screen-recorder