Why a laser still has an effective range in space

How can a laser be out of range in space if its light keeps travelling?

Its practical range depends on whether it can deliver damaging energy quickly enough, with dissipation also affecting effectiveness.

Light continuing through space does not by itself make a laser effective at every distance. The target must receive enough energy to suffer the required damage within the engagement's available time. A theoretical ability to reach the target therefore differs from useful weapon range. The reply also accepts effective range and dissipation as relevant qualifications.