Reading this thread really highlights the little thought that has been made by Epic towards customers. Some payment methods are costly to use, but are the primary means of choice in some countries. Epic's position is laughable - asking of such payment methods "why would you want to support it". How about, because sometimes that what customers want to use and is beneficial to them
They absolutely do not have to "pass those charges to consumers".
"pass those charges to consumers" and "little thought" can be used to describe almost everything about the Epic Store so far. Almost every solution to perceived problems are made to detriment of consumers. My completely baseless guess is that maybe regional pricing is one of the things Ubisoft insisted for the deal - because the do it everywhere including UPlay - and what we have now is what could be implemented in short notice. The hard part like actually implementing local currency and payment methods will have to wait.
I doubt Valve is eating "up to 25%" cost of the transactions, but they also only launch regional pricing when everything is ready. Also, it's a probably a good bet that Epic has yet to deal with a lot of other logistics problems like users traveling (which region do you show them?) and so on.