Not that I would want to preach to the converted, but a rebreather, OC setup, plastic bag, or long snorkel are just tools to do a job. We just happen to like these particular tools!
I don't actively teach at the moment, so I only do a few OC dives, when it's warranted. I choose to dive a CCR as I think it's a great tool for the vast majority of the dives I do: Wrecks, deep wrecks, critter photography (very much in the happy snappy mode) or peaceful solo dives with lots of redundancy.