I wouldn't offer them banana peels because most bananas sold are probably sprayed with pesticides and other toxic stuff. Unless it's something you grew yourself and can guarantee it's not sprayed I wouldn't risk it.
Edit: I did some searching and they also contain cellulose which is indigestible for birds
Banana peels are edible, yes. I looked it up to see if banana peels are any more toxic than any other commercial crop, and I could not find any evidence to suggest it is. So, as long as you wash it well like you should be for any fruit and vegetable, it should be safe to feed. If you want to go a step further you could opt to use organic bananas which may lower (but not eliminate) pesticide residue.
Wash the skins well before peeling the banana then offer them.
Burt often loves to peel and eat all the white insides out of the skins. I’ve seen the skins offered to birds many times and many people also eat the skins as they’re quite healthy for you apparently.
If they are well washed then yes. If your birds will eat them. Mine give me a look that says "what the heck is this stuff"? Picky little things they are. But they fight me for a taste of my banana yogurt which I end up eating in the bathroom in private...