I have read some accounts elsewhere of others using this type of water torture in BDSM play. I wouldn't reccomend it to anyone who wasn't terribly experienced in edge play. Basically the end result is the reciprocating person puking. It doesn't sound too appealing to me.
Waterboarding can lead to permanent damage, and death. Torture techniques are designed to prolong agony, and yes can eventually harm the person.
Personally I don't care either way about waterboarding, I would think that the CIA is doing damage control right now, since this waterboarding has leaked out into the public foray.
Heaven forbid the american government would use any form of torture intended to harm another. I am sure that there are other forms of torture that are used as well, they just haven't been leaked out.