I agree, better clarification/classification of errors would be nice, as well as the different tradeoffs you should expect from using a particular check. In particular with the Path() related checks, they can seem contrived when used in isolation (open() is a pretty common idiom, like you said), but they become really powerful when you chain them together:

(Path("some/deep/folder").parent / "file.txt").read_text()

Similar to black, Refurb is opinionated. There are probably going to be checks which you will ignore. Somewhat of a non-goal with Refurb is bringing to light some of the different ways of writing Python code, and the pathlib module is, IMHO, a very underutilized part of the stdlib.