Your last item is not totally accurate: Refrigerated ships are the ones where the entire vessel is temperature controlled. What Dole needs is lots of power connections ("reefer plugs"). That's uncommon but not the same as a refrigerated ship. Last I knew, other companies partly use reefer ships (bananas in bulk) combined with loading into containers.

The benefit of a big refrigerated vessel is mostly when you have a big company importing ("importers") in huge quantities and then selling it to other companies. A single container is huge, but it is way less than a whole refrigerated vessel. Part of the reason why more bananas have been shipped in reefer containers is due to companies cutting out the importers.