Well, in my experience, the 5X has also registered for many companies affiliated with the travel industry in general (i.e. if you booked a half-day city tour, etc.) and not just flight/hotel focused businesses.

Also, there are quite a few interesting smaller players in the OTA scene, as well as foreign OTAs with highly preferential pricing that can save you a fortune vs. a direct booking or using the major players (Expedia/Priceline/Hotels.com/Booking/Orbitz/etc.).

One great example is booking hotels in Cyprus via TUI DE (Germany) - some of the price differences are profound and can even include upgrades to half board/all inclusive for a lower price than you'd find on any "big box" OTA or direct.