Silmaril and BigRed56,
Lets see if the picture forming in my befuddled brain is the correct one. These training programs - ASA, USS, IYT - are purely private sector operations. The certificates they offer might make it easier to rent a boat but aren't necessarily required. Similarly they might get you a break on insurance and financing but, then again, maybe not. If you want to carry passengers for hire then you have to go through the US Coast Guard prescribed training.
To put it in terms of the aviation industry it goes like this: The USCG is the FAA for boats but unlike the FAA they only issue and govern commercial licenses. Official, government recognized private licenses don't really exist.
Have I got this right?