It should be better than submarine fibre for longer distances. The satellites will be in low earth orbit, and the constellation will be dense enough that routi

It should be better than submarine fibre for longer distances. The satellites will be in low earth orbit, and the constellation will be dense enough that routing ought to be pretty direct. You only get about 2/3 c in glass, compared to c between satellites in a vacuum. If the satellites are 500km up, so long as the distance is greater than roughly 2000km, you should get lower latency via the satellite path. Of course this assumes you don't lose too much to the MAC, and the satellites manage a routed path not too different in length to the route via the fibre (which often involves a detour to get to where the fibre comes ashore).