I understand your point, but I don't think I really understand the fee structure overall. Won't there be fees associated with storing the value, insuring the storage, converting the currency to/from Fiat, etc... These are all things that are baked into that 2% credit card fee or 5% conversion fee (FX yes?). The remittance fee is a scam -- on this we agree.
These are the things they say are baked into that fee to justify it, but the reality is quite different. The reality is that it's lack of competition, extension of credit, and fraud prevention (due to the fact that you give the credentials away fully to make a payment) that accounts for most of the fee. Still, credit cards are probably not the very best disruption target. The higher the cost, the easier to disrupt.