Just for the sake of argument, let's say he is the 8th pick in the draft, this year (about where he is projected). Last year, that draft slot paid $31.3 mil over 4 years.
Does sticking around another year and making $4-5ish mil in NIL jump his stock to a top-3 pick in a weaker draft class? For example, the 3rd overall pick paid $50.4 mil over 4 years.
That's a $23-24 million difference in NIL and total rookie contract value, which is obviously significant.
Again, not making an argument that he should do it, but I think you could argue there is some merit in the idea.
And not that it is the deciding factor, but it would also put him halfway, at least, towards a degree. For some kids and families, that is important. For others (most), not so much.
In the end, he's 99.9% going pro and no one will blame him one bit, certainly not me. For every reason imaginable that we could give for him to return, we can name five reasons he shouldn't.