[jrumbut]

I think it's the varying degrees of importance and surprise factor.

One dotfile has the maintainer's eccentric syntax highlighting preferences, another has critical build system settings needed to make any use of the code. Which ones do I really need to knand which are just conveniences for users of a particular IDE?

There are very few pieces of information where, to me, the natural place to look for it is "a dotfile at the root of the project." gitignore is an exception here.