any fork of bitcoin that can not gain enough support will become useless. it doesn't matter what it is. and so far community has shown that they have more support for SegWit because it comes from the Core developers that have been coding for bitcoin for man years. so even if they are not tech savvy they go with Core that they have always trusted not a new one.

that means even if BU or any other proposal in the future forks, they will gain very small support and eventually become like the many altcoins that have forked from bitcoin in the past and die off over time.