Originally posted by paultopiaBlack does not have immediate "good advantage" even if Benko is accepted😀 Would be strange to hope for edge with Black very early in the game, if White would not commit any serious sins. Benko [either accepted or declined] is very special opening with unique and interesting play, but unlike most gambits usually it is not about king hunting - black has nice pressure on queen side and arising endgames are often in their favor. It is complex though and demands some time and losses to get accustomed with.
I'm trying to find a good gambit for black against a d4 opening, and I keep running into the fact that they all seem to require White's cooperation. Black doesn't get any real good advantage that I can see (I'm probably wrong) if the Benko etc. is declined.
But gambit is just a mean to get active play. In Dutch or KID black has a lot of activity without sacrificing material. Look at Edmond Dantes Dutch games - you will not be disappointed!