Not really. Before AMEX, Costco had an exclusive deal with Discover. That's the definition of inconvenience. This new deal will result in a Costco branded Visa but Costco will be accepting ANY Visa card. For the vast majority of consumers this is much more convenient.

FWIW, AMEX has been doing the hard sell trying to get me to switch to a new card. So far, I haven't seen any offers worth my time. It's a shame really. I've been a cardholder for 15 years and even worked for them for a few years. Personally, I see no reason to continue the "relationship".