How do you justify CSR over Amex Plat?

It's well established everywhere that booking over a portal is a bad idea for air travel. So, between CSR and Amex Plat, only Amex Plat gives you the option for direct booking and getting 5X. So, what's the argument for CSR over Amex Plat?

For context, I already have 3X on Airfare though Amex Gold. So 3X travel through CSR doesn't make a difference. What made you decide between the two?

PS: Not planning to jump into either any time soon. Simply curious about the options.