Having accumulated points on various platforms, in my experience, United and Alaska had much better availability for close-in flights than Delta. Dunno if there's a difference between redeeming on the Chase site versus transferring to United and then redeeming, but might be worth playing with.
Agreed. Anyone interested should check out a report out of Vanderbilt, "The Loyalty Trap: How Loyalty Programs Hook Us with Deals, Hack our Brains, and Hike Our Prices."
Small counterpoint: Working in a spot where I had visibility to various loyalty programs, several of them definitely rewarded loyalty. Big spenders would get better conversion rates than the regular consumer.