I don't know if it counts as “production”, but I quite often use it to develop small GUI utilities in academic settings. Performances are bad, but when playing

I don't know if it counts as “production”, but I quite often use it to develop small GUI utilities in academic settings. Performances are bad, but when playing with relatively small datasets, the portable (Linux/macOS/Windows) GUI, the huge stdlib, the ease of deployment of fat binaries and the pleasantness of the language in itself make for a very seductive tool.