Fred, I think you've pretty much nailed it.
Regardless of all the bad press these projects are getting of late they've got one thing going for them. You can get/provide "fresh" fish year round at a stable market price. There are no limits, no 'seasons,' no 'closures,'no etc. Suspect the cost of setting up the pens is way cheaper than the cost of opperating, maintaining a fishing boat and all the other required follow-up. (e.g. canneries, etc.).
The economics of commercial fishing became questionable a long time ago. Was interesting to see/read the reasons why/why not the commerical guys gave when the boat buy-back programs were in operation.