Wiring directly to 200 amp main breaker

In wiring a split phase totally off grid system, what are the benefits of using a 60a breaker instead of just wiring the 2 hot leads directly to the main breaker?

It depends on the wire size and the capacity of the inverter. Mine has a 60 Amp breaker on the AC input so there is no advantage to wiring it to a larger breaker. Typically in my local, the 200 Amp main breaker powers the bus bars so unless I wanted to put in another 200 Amp breaker on the bus bar there is no advantage to increasing the breaker Amperage because it would also mean upgrading the wire to handle 200 Amps.