Seems like it nonetheless provides redundancy. Also, one site can only handle so many launches per day. If SpaceX gets really busy, it will need multiple launch pads to handle the traffic, both launches and landings.
But then, there may be military missions that require launching from an air force base.
An orbit from there is useless for a mission profile that was slated for Florida. It costs more fuel and has completely different ground tracks.
The sats that spacex launches for Starlink, which are about as interchangeable as you can get, are less valuable in polar orbits because they spend significantly less time over population.
But then, there may be military missions that require launching from an air force base.