You still have to switch hands between casting and palming when using a left handed reel. I use both and it's the same thing. You cast with the rod's trigger on your trigger finger then switch to a palming grip of the rod to center the mass of the reel at the fulcrum point of the rod (your hand). Since you are changing up grips anyways its as simple to just stuff the reel into your open left hand to change hands as it is to move your right hand up fron a casting grip to a palming grip with a left hand reel. I do both and it's the same thing.
The only reason I own left hand reels is so I can palm while pitching, punching or target casting (this last one is debatable because there is bait flight time). If all I did was normal casting I would just use whatever i learned 1st because they are functionally the same thing.