I'm going to take a very, maybe excessively, cyclical view on this and claim that the feds were using basically excessive force specifically to intimidate anyone who might get a similar ideas. Then again without raids, it's possible that laundered money could have been hidden while the feds were biding their time.

Is the 97% for how many were executed that way, or for how the warrants were issued? Could it be that they're just defaulting to asking judges for the more permissive version of a warrant so that they have it in case something makes them want to do it that way, but often actually knocking and executing the warrant the same way they would if they hadn't got a no-knock one?

Of course that still wouldn't be good, but less bad than actually using the ability to perform a no-knock raid 97% of the time.