Or do they simply serve to make one feel like he gave it his best shot?
Obviously, there’s no admissions officer that we can speak to here, but something given is definitely better than nothing to show that you’re still interested in the school and want to attend. Shows you’re making an effort that could actually be evidenced on your application. It’s very hard to imagine how a deferral letter could hurt someone rather than help them. Don’t you want the best shot at getting in? Contact admissions as best you can and let them know this is still a school you’re interested in.