I'm right handed and until about a year ago I used a left handed crank spinning reel and right handed crank bait cast reel. I asked the same question and tried a left crank bait cast reel and liked not switching hands. Now I use both and find it less tiring when fishing many hours.

There's a definite speed advantage for a right hander to cast right and reel left with casting equipment. You can roll the the next cast out as soon as the the bait clears the water without changing hands. That said, I mostly have right cranking reels because of accumulation over the years, but if I'm hosing close cover with a crank or buzzer I like the left crank. Also, it gives a bit of a break to the muscles after a long day of fishing to shift to the left crank. However with spinning it feels more natural to me to crank left.

It probably saves you hundreds of movements a day to cast rh and reel lh...

I switched last year it was easy to get used to, just dont take any rh reels with you and youll have it by the end of the day.