The distance between stars, and even planets, is absurdly massive, making stories involving visiting multiple galactic locations difficult to tell. The FTL drive allows a story to take place on galactic scales in a reasonable amount of time.
Humans cannot travel faster than light, but probes can. The League of All Worlds sends an orbital strike via a probe after learning about the invasion of Rocannon's World.
Slower than Infinity has an FTL drive which can only operate far from gravity centers, and also does not affect normal space momentum. Thus, to bleed off a high momentum, ST∞ must decelerate as it passes through a solar system, then use the hyperdrive to navigate around the star's gravity well, dropping back into normal space at their original entry point to continue their velocity-matching burn.
Faster than light drives are common among the species in the Ringworld universe. The reward offered by Nessus for his Ringworld exploration team is a ship called the Long Shot, which has a much faster FTL drive than any other known.
The premise of this anthology is accessible faster than light technology.