The only minor counter-argument would be laziness as a security threat: the more difficult you make the process, the more likely the user will skip seemingly useless steps, thus compromising security.
I generally avoid non-trusted utilities altogether. I am most likely to load up data (for the use cases mentioned in the extension description) into a Python shell and deal with it using json, base64, pprint and similar modules.
Some things I can do with regular POSIX and GNU tools directly from the CLI, so I'd trust those too on my Debian/Ubuntu systems (where there is usually a guarantee you can get the source code for the binary you are running). It's definitely possible Debian/Ubuntu experience a supply chain attack too, but it's significantly less likely than a random library from github IMO.
https://wiki.archlinux.org/title/Bubblewrap
https://wiki.archlinux.org/title/Firejail