It’s also highly useful when planning multi-system jumps, too. Say you took a contract that tight on schedule (as all the better paying seem to be), when you do your own jump, from what I’ve seen you tend to end up in the quadrant closest to where you left. By looking at the pda map before jumping, you can confirm which quadrant is closest to the target station and then try to plan your jump route so you end up there, rather than having to float across half the system to dock.
Not always easy, and many of the contracts are simply impossible to do without a better jump drive I think (Sagan to Leo in 3 hrs?), but it does make jumping a more involved affair than just “click on a system and jump.”