Am I missing something here?
No, you're missing nothing.

But IHG usually(not always) has cheaper hotels than Marriott or Hyatt in most area, and you will usually get 1 cat upgrade, late check out, and free drink coupon.
For ICs, just for $200, you will get 1 cat upgrade, amenity, and 4pm late check out, which is huge.
For someone staying around 50~60 nights, I'm sure that Marriott, Hyatt, or Hilton would be better program. But if not, IHG has its merits.