The basic answer is don't use AMEX travel to book airline tickets unless you are getting a substantial discount on the fare. Such discounts (particularly IAP) are sometimes available but IME it's becoming less and less common. My last purchase was about a year ago. I still check the fares for international long-haul but the meaningful discounts are few and far between. Given the hassles of changing or refunding an AMEX ticket, I won't book unless there is a truly substantial savings.

OTOH, 5x MR points for booking through the airline is one of the best benefits offered by any credit card.
IRROPS refers to day of travel disruptions, and the carrier is responsible for rebooking.

The problems arise when have a schedule change or need to make voluntary changes prior to day of travel.