R is considered “full fare” as per the AA upgrade rules. As a result upgrading with 25k and no copay is at least more accessible to nonEXPs and arguably a better deal that using a SWU (which could be saved for a fare requiring a copay).

Edited to add:
Surprised nobody has noted this. The surcharges when flying KE are noticably lower than routing via HKg w Cathay/Dragon. I was able to get KTM-JFK for $1600 RT for adult and $1300 RT for 2-11 yr olds booking via ICN. You miss the F upgrade potential, but that is a cheap fare!