It provides screenshots, categories and icons for Flatpak packages. AFAIK those aren't provided by AUR or the official Arch repositories. Icons seem to be integrated for some official packages at least.

A Shelly in-built way for user contributed additional data for Arch packages could be a way to tackle this. But that needs additional infrastructure, developers and volunteers who curate the contributions.

Shelly is a nice frontend. Octopi is too, to quickly check PKGBUILDs, show contained files or open the respective AUR page.