I've stated it before on other threads: I have never bought a coin because of the CAC sticker but I consider it a nice bonus or reassurance. If I decide I like a coin, particularly a more expensive coin, I appreciate that someone that knows a lot more about grading than I do deemed it an A or B coin for the grade. Even dealers I know that are anti-CAC have great respect for John Albanese. This doesn't mean I only buy CAC coins or that I have never passed on a CAC coin. But I appreciate the company and think it has had a positive effect on the hobby. For whatever reason, a lot of collectors on coin message boards tend to believe they are as good at grading as professionals even though the professionals have done it for a living for years or decades. For most of us, it is a good thing to admit that professionals know a lot more about coins and grading than we do. For those that don't like CAC, I would suggest they either not buy CAC coins or ignore the stickers in their buying decisions. However, 900Fine said it very well here on another thread -- I seem to be seeing the stickers on a lot of the nice coins I come across. Finally, something people forget is the sticker is not just an indication of an A or B coin within a particular grade, but also a guarantee against coin doctoring and an offer to make a market on the coin. In other words, CAC stickers the coins they would be willing to buy.
There is some truth in your comment, but it is also misleading to a degree. For CAC will not buy all coins they place a sticker on - but they will buy some of them. And it is important to note that they will pay wholesale - not retail. In other words, you could just as easily sell the coin to any other dealer for the same price.