ok im not sure if this is actually spoiling or not, so i'll just conceal it just in case.
<SPOILER?>
<span style='color:#D6DBE0'>well im sure the details of it arent something we are supposed to think too much about.....but it seems to me, that the true purpose of there being a branch family is for protection. The duty of the branch family is to protect the head family, and since the seal will destroy the byakugan abilities of theirs, they can afford to put their lives on the line without fear of being killed and their abilities stolen. I&#39;m sure they try to keep the two families fairly balanced, and won&#39;t just make EVERYONE except for the leader and the decendent become a branch member. But in any case, hinata wont be able to serve the hyuga family much as a branch member anyway </span>
&lt;/SPOILER?&gt;