Curious...how many racers run an alternator?

I run a single field Mopare alternator turned around since I run a motor plate. I have a cut out switch that I flip off when I start my burn out, when I make the turn out, I flip it back on to charge on the return road. This has worked well for me for 11 years & counting.
I always wondered about that (switch on the field wire). Does it give a small bump in ET like not running a belt?