From inside the ship, light speed is faster. You travel arbitrary distance in an instant.
Outside the ship, everyone else sees you moving 1 light year per year, but for passengers, the voyage is essentially a forward-only time machine.
From outside the ship, warp speed is faster. Observers will see the warp bubble with a ship inside it moving >1 light year per year, and because it will arrive at its destination before light from the ships own past will arrive there, it acts like a view-only backwards time machine.
for the passengers it's a backwards only time machine, since they travel back to a few centuries when they arrive, because that's the speed it would take them with light speed