Well, they are annoying, but in the last few weeks I got an offer for Freedom Visa with a $300 sign up bonus, and then an offer for Sapphire with a $500 sign up bonus. (I ordered both)
I just got another Sapphire preferred offer with a $500 bonus, but I don't think I will do that one...
But the $800 bucks for doing nothing was a nice little perk.