What's holding them back? Mostly the inadequacies of current battery technology to the power requirements of modern racing; you just can't stuff enough electricity on board, at the weight target, to make a compelling race car, though some series are trying.
But hey, that's pretty much the problem with all EVs (again excepting the 85 kWh Model S) anyway, right?
Enough of these abstractions; lets see what it's like to turn some laps in Nissan's Leaf Nismo RC racer, through the eyes of regular Leaf owners.
We bet they don't whoop and clap like that in their own cars.