Most do not get checks now. They get welfare cards (debit cards). Caliornia tracked the spending and CA welfare dudes spent $69 million in three years out of state. A lot of it at Nevada casinos and Gulf Coast cruises.
I was advised that at the first of every month, there are a HUGE amount of Dept of Treasury mail and SS mail.
My wife works for a large school system, and they still send out over 50% of the Payroll checks by USPS.