Not all features are for everyone. Maybe you're experienced enough that showing a graph seems like an overkill when you can just read the warnings.

But I can imagine for someone that's more entry level the graphs could make it easier to understand what the problem is

I mean, it would probably make sense to make this optional to accommodate as many preferences as possible. I, for one, prefer to get the human readable message right away instead of having to use another tool for it.