Today there's no way to disable it, I searched through my Firefox Mobile settings. So I'd say it's for very "power" users.
And why enable it by default, why not disable by default?
Also, sibling comments say iOS is already asking for the permission, why not just copy it?
it does exist in `about:config`, which could be made as a UI setting instead:
`media.peerconnectin.enabled`.
on cromite[1], a hardened chromium fork, there is such a setting, both in the settings page, as well as when you click on the lock icon in the address bar.
[1]: https://cromite.org