Hate to say it, But yes. i think its a waste of money.
There is no real product out there that you can leave on for years without taking care off.
Most dealers dont prep the car before sealing the finish in, so your left with a not so good, but reasonably protected finish.
Customers come to me for the same sort of treatment. Infact, sytner & Stratstone group send people to me when they know they are picky, or just an enthusiast.
What should happen is:The car should be washed, Then clayed, Then washed, Then Fully corrected, Leaving the paint even better than when it comes off the product line.
Then you should seal it, and wax it once a month.
Best thing is, This service is cheaper than what more dealers charge just for the diomandbrite.
If you want any more info, just ask, am more than happy to help.
To see some cars, which have had this done, here is the link
www.portfolio.cleandetail.com