I can see some big disadvantages from the employer’s point of view. Depending on what type of business they are in, they may need to collect their accounts receivable in order to have money in the bank to pay their employees.
Another issue is payroll taxes that need to be paid to the government. For businesses above a certain size those payroll taxes need to be paid every payday. If payday becomes everyday, the business would also have to pay the payroll taxes every single business day. This could add a lot of back office cost to the business to process payroll.
It is not as if it is 1967 and Marge in the Accounting Department is hand wring your paycheck and entering the payment and associated payments into the green accounting binder.
It’s all rather seamless and even systems like SquareUp can take payment and deposit that money into the seller’s account on the same day.
The question we should be asking is ‘Why do employees extend two weeks of zero percent credit to their employers?’