Sharon - I think not offering points for incidentals is another one of those things that makes CY a less likely choice for elite travelers. Why give away more than you have to, when you're doing pretty well not giving it away?
The SHS brand isn't as well known as the CY brand, and the FI brand isn't as highly perceived. MI likely maximizes its overall bottom line by getting us out of the CYs and leaving the space available to the general public, since most of us would stay in a SHS, not a non-MI property.
Heck, I think most of us like the room set-up, bedding and better standardization offered by SHS anyway.
Personally, when I need to be somewhere, I use the address search function on the MI site. If there are a FS, CY, SHS and FI close by, I look at price. If the FS isn't too much more expensive, I say there. (We have good corporate rates at many hotels.) Otherwise, it's usually the SHS before the CY of FI, unless one of the latter are significantly cheaper. My tie breaker on those two is Trip Advisor.