Also, much of the benefit of credit cards is from the fraud protection and mediation that companies provide -- it's not so much that they're loaning me $X00, but that they're covering the transaction details against fraudulent use and provide a dispute mechanism if don't feel the merchant has lived up to their offer post payment.

I find it much more likely that MC is trying to be the MC of cryptocurrencies -- eg, by packaging up a USB dongle that automates transactions using "secure" means, which they then insure against abuse. From that perspective, ETH makes a reasonable platform.