It's dumb but it's been retroactively taken to mean that it has a Class 0.5 hyperdrive, whereas a Star Destroyer has a Class 2. (Smaller class numbers are faster.) Light speed in Star Wars can be much faster than the speed of light.
But then, pretty much everything to do with specifications and numbers of Star Wars tech is a clusterfuck of technobabble that makes Voyager's look coherent.
The cope for awhile was that it was 1.5x lightspeed while in hyperspace, which also distorted distances, so you got much, much faster travel speeds without messing with relativity.
Then they decided it was a multiplier applied to how long it took to travel a certain route, so lower was better.