One thing I don't recall seeing much discussion of in the cackhanded debates that come up from time to time --
I am a strong believer that effective casting results from casting efficiency, and efficiency is to a great degree a function of good ergonomics. Well, a cackhanded cast has very different body position, thus, different ergonomics to manage. So, if you want to cast cack- instead of switch- handed, you are basically doubling the numbers of casts you must learn. That's even if you believe effective ergonomics are possible for cackhanded casts,which, for touch and go casts, I question is possible. Switching hands, it may seem awkward at first, but the casts off either shoulder should be mirror images of the other. Establish correct form on one side, you can focus on mirroring it.
I admit this is probably not as big a consideration with really short (skagit heads) cast sustained anchor. And, in the case of injury, well you do what you gotta do to manage.
One weird thing -- I've noticed that since starting speycasting, my ability to use my weak (left, in my case) hand in everyday situations has improved quite a bit. Something is going on in terms of training/conditioning/re-wiring brain pathways.