Really? That's surprising. I guess if you mostly used it on servers or if you used default GNOME/KDE you might not run into it. It was the go-to screenshot tool for anyone using openbox, i3, most small WMs. A more universal tool than whatever DE-specific thing GNOME would use. You run it from the CLI, but commonly you'd bind a key to run your one-liner(s) of choice. Commonly used to do crop-style screenshots similar to what macOS binds to cmd-shift-4. Tons of people I know were using it for years. It was somewhat overtaken by maim in later years, and then on Wayland replaced by slurp/grim, but I still call screenshots "scrots" a lot of the time.
