Back in 1988 my life long companion Arthur Its began to get real bad in my Right hand so I spent the better part of a season teaching myself to cast left handed. After a while I got it but struggled a bit, still used right hand until pain / weakness got too bad. In about 2005 new meds made it possible to use my right almost all the time, but I have gotten so used to using left hand some times I just start casting that way. When I guide a beginner or do a casting class at the shop I try to show them with my left hand as it has a better stroke and I tend to carry the line and not shoot it like i do with my right. I don't feel casting with either hand make you Elite it just make you more versatile.
steve