Originally Posted by SpaethCo

I look at this approach like insurance. In general, insurance is a money-losing endeavor unless you run into a low probability event that causes it to come into play, then it can completely save your bacon. The Platinum card is loaded up with tools to fix situations that go wrong - purchase protection that includes lost items in addition to the standard damaged/stolen, an extended warranty program serviced by an in-house division, and return protection. The customer service isn't always going to be perfect, but I feel like odds are in your favor of positive outcomes when it comes to transaction disputes, getting an emergency replacement card, or other common issues.

When it comes to prioritizing on just earning, as an example for online shopping doing an ACATS transfer of $100k of portfolio holdings over to Merrill Edge and getting the customized cash rewards card is the "on paper" winner because you can yield 5.25% cash back. ME is a bit of a train wreck, money movement is glacial, and every UI you interact with feels like a 90's Comp Sci group project.... but those aren't necessarily show stoppers. The real trouble comes if you ever have problems with one of your online purchases. BoA Customer Service is mediocre in good times, and atrocious when you need them to actually fix a transaction problem. I've also needed to interact with BoA customer service more than any other card issuer because their fraud detection algorithm is twitchy as heck. (My oldest BoA card is from 2003, so it's more than just new account training)

If you have a need to make a purchase protection or return protection or extended warranty claim, Amex actually honoring those policies can offset years of additional cash back/rewards you might have received on other cards... but those are also low probability events.

What makes the Platinum tough for me is that it's not just the lower earning rates, you have to accept that the card won't have universal acceptance so you'll need a backup, and you have to be okay with the annual fee or running one of the hoop jumping courses if the credits don't line up to your natural spending patterns. Still, if I'm going to have a problem with any transaction I feel like the Platinum card gives me the best shot at a favorable resolution, and that's why I can see being completely on board with making that the last card standing if you're going to whittle things down.