I'd argue that the company does get something back, potentially. Many companies will say to come back after 6 or 12 months to re-apply. If they like a candidate

I'd argue that the company does get something back, potentially. Many companies will say to come back after 6 or 12 months to re-apply. If they like a candidate well enough to really mean that, wouldn't it help the candidate to learn what they were otherwise weaker with so they can work that out before returning? But that's a fair point about waivers not being legally binding.