So SpaceX is building a second orbital launch pad at Boca Chica even though they haven't finished the first one. They also have plans for an expansion including a THIRD orbital launch pad. Each pad will have its own tank farm capable of holding all the fuel required for a launch.
They are also building something that demonstrates the advantage of methane + LOX, a fuel plant to allow them to manufacture all their fuel for the site on the site. Takes a lot of tankers to fuel a SH and Starship combo.
I think the launch pads are based on this being a spaceship construction site. They will (IMO) launch on their first flight from here and land elsewhere on a pad at a "spaceport". Given the volume of noise to expect from 28 raptors at full power for a launch you won't want to be living anywhere nearby. Also with the potential explosion of a combined SH+SS FULLY FUELED you don't want people or anything else anywhere nearby outside a bunker. The 3 exploded SN8-10 only had a very small % of their possible fuel at the time of explosion. So imagine explosions perhaps 150 times as great (likely several kilotons equivalent).
This works well with the converted oil platforms for launch sites as any structures could be under an (armoured) landing platform and most people/equipment could be a couple of kilometers away and relatively safe, even further away if needed, even subsurface. At sea the platforms could be many kilometers apart if needed. Command posts could be on ships. Setup off shipping lanes should be possible so you wouldn't need to worry as much about other ships or aircraft not destined for your launch site.