Well, it’s on the internal, so it doesn’t hurt saying you don’t allow usage of your character without your permission. I don’t think anyone around here would use it actually, given the fact that anyone who has access to the same packages can recreate it, but if it pops up in a random google search a stranger might want to take it, etc… So if your intention is to not let anyone else using it and you state it clearly, if later it appeared somewhere else you could back your legal claim against it. 🙂
From our part, we like going through images uploaded to our forums or sent to us directly from time to time and use selected images on our social platforms, etc. In this case if we selected your image we’d reach out to you to ask for your permission. Without the note we’d just use your image and credit you for creating it, of course. 🙂
This is my take on that sentence, and I’m okay with it.