The satellites are on Low Earth Orbit (LEO), so they are much closer to Earth than typical communication satellites. When the distance from ground station is 1000-1500 kilometers up, latency is not a problem. In fact, latency via satellites may be smaller than through fiber as speed of light is greater in vacuum. IIRC in fiber it is something around 0.6c, so a 40 % off from a space-based approach. Also there's probably going to be more switches along a ground-based path than along the satellite-to-satellite route.