This is most useful for any non-JW who has JWs as friends or relatives. This group has the peculiar position of never having been JWs and, because of this, JWs are much more willing to discuss such things with them. The more educated we can make this group of the population the better equipped they will be to help JWs who call.
It is potentially also useful for people in situations similar to my brother's; my niece is planning to get baptized but has agreed to talk with him first before deciding for sure. It would also be useful for people who are trying to reason with relatives/friends who are not yet JWs.
This is something JWs really believe they are knowledgable about, but the Bible can be used to very quickly remove every point of reasoning they have on the issue of celebrating birthdays. The point that Romans was written to both former Jews and former pagan Gentiles removes the need to argue over whether a certain celebration has pagan origins. Romans 14:1-18 says not to judge people about the observance of days and the instruction was given to former Jews and former pagans.
I agree that no hardened JW would even discuss the issue with anyone who has been a JW. In my opinion, most JWs are not hardened JWs. There are some who post here whose family still talks with them even though the rules say not to do that.
—AuldSoul