Okay, I won't use prefer to use raw bananas for sure.
But, I wish to understand why are over ripe bananas required for the muffins. Why won't ripe (yellow) bananas do?
From: https://cooking.stackexchange.com/a/24652/6168
You want to wait until they're so ripe you wouldn't want to eat them – blackening skin, very very soft.
Best Answer
They are easier to mash (so that they incorporate more smoothly into the batter), sweeter (more starch has converted to sugar), and more aromatic when overripe.
Still, you can get quite a good muffin or banana bread from fully ripe, but not overripe, bananas.