They can access the bank accounts, but can they legally perform any meaningful transaction with the data/money they access? For example-- suppose that person

They can access the bank accounts, but can they legally perform any meaningful transaction with the data/money they access? For example-- suppose that person dies and these 7 relatives access the account and wire themselves some money. With no other arrangements made, doesn't that constitute bank fraud? On the flip side-- if the relatives also have to go through the time-consuming processes of meetings with an estate lawyer and bank managers in order to fulfill the wishes of the deceased, what function does the cryptography perform in this case?