Hypergamy is about social status. Most people assume it's all about money but it can also be about "social status". A man is popular or appears to be successful. Gold diggers are simply who have no intention of having a long term relationship which includes marriage. A good example of the gold digger is Rich Piana's ex wife. She stole money from her ex husband who ended getting tossed out.
Alan Rodger Currie points out that men in the manopshere complain about gold diggers while spending money on women. But here is the truth. Most men are spending minimal amount of money typically $10 to $20 tops. Unless she is spending 2 to 3 meets or dates every day. She can only get about $600 to $1800 worth of free meals or drinks. In the real world most women are not dating that often. At best she is probably getting free food and drinks that around a few hundred dollars. A gold digger isn't going after men like that. She want each man to spend thousand of dollars each money.