It doesn't increase connection speed, the downlink to earth is a factor of the frequency and coding mechanism. What these links do is allow satellites to pass traffic between each other rather than down to earth and back up again. The way this works best is if each unit in orbit has data held in cache. That way a request from a customer only makes the round trip a limited number of times.

It can also be used to extend range of in-orbit terminals when they are out of range of an earth based POP by passing that data to a satellite that is in range. But 100Gbit isn't very fast, so that'll end up being a balancing act.