Complexity is our friend. I daresay American Express's average redemption cost per point is lower than Chase's cost, and this allows American Express to offer more value to those who are sufficiently engaged to find it. I consider this good program design.
I totally agree, even though I hope AMEX brings in more physical restaurants than the Grubhub stuff because the latter has serious geographical limitation.
At least AMEX does not engage in some bogus claims on their travel benefits like Chase does.