On the other hand my general view is that I will always prefer the system install of a language environment, because I know the distro is going to take care of

On the other hand my general view is that I will always prefer the system install of a language environment, because I know the distro is going to take care of ensuring it works with the distro config, updating it with security bugs and making sure it doesn't break when I update the distro in future. In fact "doesn't exist in distros yet" is one of the major reasons I haven't got round to investigating Rust yet. And the distro themselves will want to be using their own packaged version of the language to build any other programs that are written in that language, for reproducibility reasons.