OTOH, both CSR and Amex Plat have high actual AFs and even high "net" AFs (ie, they don't have tons of credits to lower the "net" AF close to or below 0, like some other Amex and Chase cards do). And it turn, that keeps them from being "best" for people who loathe paying high AFs.

And so if someone doesn't spend much on airlines because they want to do most of their flying with miles (except maybe a handful of cheap domestic flights a year), do those cards really work for them? It seems to me you've got to buy a lot of travel before the 5x overcomes the nigh "net" AF, compared to 3x on the Amex Gold where with full use of credits you can lower the "net" AF to just $30.