@Sarcasm But he's still missing part of his soul. That's why he's unable to use his true form with four arms. All fingers are equally strong but he's not complete as long as one of them is still missing. All parts of an engine are equally important but it needs all the parts to orderly functioning. Sukuna can just eat an infinite number of strong sorcerers mummified and go beyond 20 fingers if it's that single.