I don't agree with your statement that "anybody who doesn't [know what a userscript is] won't need one". If it was explained better there might definitely be people who could use this and become interested in this, without knowing its name before.
This might be the first time some people hears about userscripts. It is certainly possible to have been an internet user for many years without hearing about them. Does not mean they would not be useful to a subset of such persons.
Also [1].
> Contribution
> You are absolutely welcome to contribute code to GitHub.
> You are welcome to help with this website too. Documents, improvements, articles about Violentmonkey, etc.