There's literally no downside here.
A) If he somehow gets the waiver and can play at some point this season, he'll definitely contribute and would play 2 years or portions of 2 years here.
B) If he needs more time to rehab, then RU has no need to go to the portal next year and fight for a recruit. Jeremiah will be here in the system for a full year and will hit the ground running with Dylan, Ace, Simpson and others. Austin Williams and Fernandes will be out, Jeremiah steps right into the lineup next year.
C) He's a Midwest kid, who is familiar with Phily and the Jersey regions. He's not going to have to adjust to the culture of the NJ area.
D) I don't see this being worse than giving a walk-om a scholarship. Williams as an immediate impact player next year, with a full year in the system OR a nice gesture for a walk-on??