I think I'd change the title to '9 Reasons...' and add THE major reason for holding one of the Amex color cards, which I've never, ever seen included in any of these 'X Reasons to Hold...' articles is that
The Amex color cards are CHARGE cards with no pre-set spending limits.
Although I have healthy limits on my Chase SR and Capital One Venture X, it's always nice to know that if the chips are down and I need to process a big transaction, my Green Card is ready to go.
I just hope that Amex doesn't nerf the Green Card when it 'updates' the card, which I'm sure is coming sooner rather than later. It has been awhile and Amex just can't seem to leave a good thing alone.