WePay has managed to differentiate itself and stay independent in the credit card API / marketplace payments space..I've been asked to explain WePay's place in the market before and have been unable to
Because contrary to your first statement about WePay "differentiating" itself, it didn't. There has been little to zero differentiation among the companies who make money moving money around, skimming "2.9% +0.30" off the top every time.
What's happening here with this funding round says nothing about WePay being special or different... this is merely evidence of consolidation. If there's no true disruption, cartel entities that elect to cooperate tend to squeeze each other out on a LIFO basis -- "Last In First Out". The cartel gets bigger and stronger as it melds into an monopolistic oligopoly.
WePay just happened to be one of the first players, which is probably why it survived. Stripe and Balanced soon thereafter had an opportunity to strike out and differentiate (yes, on pricing; because when your product is money nothing else matters) they were both weak and chose to assimilate into the amoeba matching pricing, not challenging it.
HN is well aware that there's now one fewer player in the cartel with Balanced ... um, a sinking ship. Yeah, they threw me overboard (http://ink.hackeress.com/2015/01/why-im-boat-rocker.html), and I'm not surprised the LIFO model is playing out as expected. The Balanced engineers I worked with were all awesome, and we had the smarts and tech to compete. But in order for the trend to be away from oligopoly -> monopoly, companies _have_ to let price be the factor that drives competition. Offer more for less, and you will win market share. Take the momentum away from the amoeba, not into it.
But they didn't believe me.
There's still a huge opportunity for anybody with the guts to do it. Crowdfunding / do-gooder sites that tend to raise money. Indie freelancers.. there are more than enough people who care about price of moving money enough to go low-cost over big and shiny.