If your son plans to use his devices until they wear out, engraving would be a good way to prevent thieves from profiting on the resale of his electronics. If he expects to resell them in a couple of years, it will make his items less salable. Engraving won't stop thieves from selling his gear in underground ways or from replacing the components that have been engraved.
If his equipment is truly valuable and theft from student rooms is a problem, he could get a laptop safe
like fancy hotels have in their guest rooms, to stow his gear in while he's out of his room.