Nowadays, when users wants to interact with Nuvola Player in command line, they have to type long commands such as flatpak run --command=nuvolactl eu.tiliado.Nuvola track-info instead of plain nuvolactl track-info. If would be useful if there was a Flatpak portal that would let Nuvola to create the nuvolactl alias upon user's request.
flatpak run --command=nuvolactl eu.tiliado.Nuvola track-info
They would have to be prefixed with the app-id to be remotely secure. so eu.tiliado.Nuvola.nuvolactl or something. At that point it makes more sense for the user to just make an alias in their shell.
This doesn't seem like a portal feature to me. The recommendation to just make a shell alias seems right.