Starlink just launched on Sep 14th 2021 a new batch of 51 new satellites fitted with inter-satellite optical links. This technology was supposed to be available right away, however it seems it was more complex than foreseen to implement. All new satellites will implement this laser technology (at this stage there is no information on the performances). Laser Inter Satellite Links (or LISL) present two important benefits: less ground infrastructure is required and data transferts are much faster.
Without LISL, data is transferred directly from the customer antenna to the satellite to the ground station: when the satellite moves away and disconnects from the ground station, signal is lost. With LISL, it is possible to have less ground stations eg extend coverage as signals are transferred from satellite to satellite until it reached a ground station. It also opens new markets (oceans and polar regions) where ground stations could not be implemented.
On an other hand, lasers present another advantage: signals go faster in the void than in glass thus laser links are faster than fiber and Starlink could compete with some fiber optic services when speed in key (like financial services).
The following video explains these issues very clearly.
More info here