Praeceptor
Marquis
As it is common to build the GB before reaching the era anyway, this GB would help players in earlier ages to go forward quicker, as they are not as "forced" to stay in the same age as before to hoard current age goods for the coming ages (Techs/GE-Negotiation/provinces). But yes, for players currently in VF, this GB probably is not really worth building due to huge stock piles of current era goods.
The trouble is that players who race through the eras are the ones who start calling their neighbours bullies when they are attacked. In my view, if you don't have enough goods to go to the next age, you probably shouldn't.