Some of the major projects out there don't even have a Bitcointalk ANN thread. They don't feel it's important, and it's one less point of annoyance for them. Having to fight with people who say, "I didn't get my bounty."

And these projects raise tens of millions of dollars without them.

So if a coin has that potential, I think it's best for them to forgo a bounty campaign. Especially since the reality of the matter is that it just creates "spam" for bitcointalk.