Which then begs the question as to why JumpShips have station keeping drives at all...
SHH! BattleTech starships have station keeping drives! Don't look too closely at canon, dangit! ;)
Actually cray you miss out on opportunities to explain canon. Many of the problems in Battletech, though not all, have a plausible explanation that you can add to canon that explains prior unexplained canon tech.
You need station keeping because you actually need to remain in one spot, or at least to fall at a known rate. Jump drives are not random, they are very precise, and while most jumps are made at zenith and nadir zones (I cant really call them points) it is a good idea to know where you are so you can jump accurately.
Jumps need to be made towards set target coordinates, these themselves can be very precise and can allow for jumps into pirate points if your star charts are accurate. But your jump is only as accurate as your fix on your current position. If you can moderate your position relative to absolute point of zenith of nadir, or your pirate legrange point, you can jump accurately.
We can take this further and answer yet unasked questions.
Normally this doesn't matter too much but it still does. We must assume that jump zones at even zenith and nadir points are coordinated to minimise chances of misjumps into another vessel. While this can happen anyway, and is admittedly unlikely because of the vastness of space, its is a viable concern if jumps are as accurate as they are made out to be. It would be a suicidal thing to do to jump directly onto the absolute zenith or nadir coordinates, in case another incautious jump navigator did the same. So how do you make sure your jump is to a safe location. You ship has a registration code right? It probably has a code for the jump engine too, a unique serial number at at least unique to your factions registry. Say your ships KF drive is Lyran registered and is given a number of #51023, that or a set factor of that is the number of km you dial in as jump-exit coordinates from absolute zenith/nadir for your jump. You can randomise the direction for the ship or coordinate them for a convoy so that your jump arrival coordinates can't be intercepted, and remain together, but so long as that unique distance is kept you are guaranteed never to jump into another vessel. This way you can plot jumps based on a set unique numerical variable that doesn't require prior knowledge of other traffic.
Station keeping then becomes important again to guarantee you never drift off into the path of another jumpship. While the vastness of space makes KF navigation accidents unlikely they do happen and are horrific when they do, so it would pay for jumpship captains to keep station keeping and obey navigation safety protocols.