Freewheel vs cassette geared hub motors serviceability
Whether the freehub rachet mechanism is servicable depends on the design of the hub. Nominally the pawls and teeth are separate steel parts in an aluminum hub body and therefore replaceable; but only if the hub manufacturer makes spare parts available.

Something else to consider is that the freehub version will be substantially stronger. The drive side bearing is further inboard on the freewheel version making the axle prone to bend or break.