What does extra toggle do in LEGO batman

Nothing. Not that I can tell.

I had a similar question. After a while of looking online and a bit of experimenting myself, I found nothing. I know that in LEGO Star Wars I-III and LEGO Indiana Jones it let you play as bonus characters in Free-Play mode. I knew for LEGO Batman It had to be different, as I tried multiple levels with empty hands. I was a bit frustrated while looking online, as many people who had never picked the game up but had experience with other LEGO games explained it unlocked bonus characters for Free-Play. It does nothing.