Make the banks only hold 401K money that was requested from an agency for 1 day not 3

Why should banks hold a person's 401K money that was drawn upon from a 401K agency that sends the money to a person's bank account?  Currently the Banks hold it for 3 days to use it for their use and then they deposit it into the bank account of the end user.  People worked hard for thier money, the Banks should not profit from people 401K money.