The addition of “withdraw” might simply be a way for USNA to make it easier for candidates to indicate their desire not to continue with their application. Many ”candidates“ are put into the system because they filled out a form, attended NASS, etc. Many of those have zero intention of even applying to USNA, let alone completing their application.
In the past, the candidate MIGHT tell the BGO, but USNA needEd to hear it from the candidate. So the BGO would urge, encourage, etc. the candidate to tell USNA. But they actually had to send an email and many just didn’t do it. This makes it really easy.
It really saves a lot of effort for everyone If a candidate who doesn’t want to pursue an application withdraws. That candidate no longer gets unwanted emails from USNA, the BGO doesn’t have to waste time following up, etc.