To me that's not the point. The point is, it shouldn't be effective. People keep bringing up "Why are you doing that?" The question I want answered is, "why does it even work?"
As far as rating mattering - if they do, it's very little. A weak RTE WR doesn't seem any worse than a 99 RTE WR. I have Mason on the Ravens - he doesn't run routes any better than Clayton or Washington. Or Ray Rice for that matter. Or even Heyward-Bey or any other not-so-good rookie WR I can get off the waiver wire.
I have Ray Lewis at LB - he isn't a game changer a lot of times. He doesn't rack up tackles. He doesn't play any different than the Joe Average LB the CPU has.
The difference between Asmougha and Johnson at CB for the Raiders - not much. The AI threw all over Asmougha just like any other CB.
Merriweather for the Pats plays like Ed Reed for the Ravens, yet Reed is 99 and Merriweather is in the low 80's.
The only place I notice ratings making big differences is at QB. Using Flacco and Russell is like night and day. Brady vs Russell is like Earth and Mars. RB - the difference I notice is in speed more than anything else. Likewise for WR and DBs.