Why charcoal is better
In a rotisserie, the chicken hangs right over the heat. Nothing in between.
With charcoal, the fat drips off the chicken onto the hot coals. It turns into smoke and rises back up through the meat. That's what gives you the deep golden skin and the smoky taste.
An electric element can't do that. There's no smoke.
You can also change the flavour by changing the charcoal. Oak, marabou, quebracho — each one tastes a little different. You get to choose
Charcoal Rotisseries: Why Chefs Are Choosing JOSPER