In my own opinion, why BCG is worth less than BCH is because BCG were not properly advertised. There were more negative topics that I read rather than positive news about BCG. The marketing group failed to make BCG more popular or the strategy they used was not effective to lure users.
Sorry maybe you mean it is BTG not BCG as you say, indeed the creation of BTG still be a question. this month segwit2x canceled but bitcoingold already created, we didn't know what is going on. 
but if for now I prefer BCH.