Here's the underlying math for the inflection point between the two methods:
cash rewards program vs. points redemption: $ 135 base + 0.0125 (x - 17,000 spending) > 0.01 x. Solving for x gives you $ 31,000.
See related:
Rewards programs move toward flexible, immediate spending, Travel rewards vs. cash back: Do you really want to be pra
Rewards programs move toward flexible, immediate spending, Travel
rewards vs. cash back: Do you really want to be pra
rewards vs. cash back: Do you really want to be practical?