Out of all the additions to punctuation I’ve seen this is the one I find myself needing most often. Interrobangs are easily written as “?!” and even most other ones can be quick fixed with storytelling like “said lovingly”, “said with authority” and whatnot.
But “Is that the best, or is it just what we have?” is an absolutely horrible thing to write punctuation for when you mean it as two connected questions like “Is that the best? Or is it just what we have?”
It should obviously be replaced with a question comma. There are so many cases where you also have the question in the middle of the sentence such as “Is that okay (question comma) because I don’t think so…”