Been a long time, but there actually is a reason.
Do you put your shafts in tip first or the joint first? If you do the tip first, then the chalk build up will probably be greater, but what's nice about this is when you travel allot.
The shafts will not rattle around. ESPECIALLY if you leave em in the car trunk. Car rear ends always Hop at high speeds, especially the fwd cars with more weight on the front wheels.
I used to shim em up (tips up) with a piece of foam when traveling. The shafts moving around in your cue case, when headin 'down the highway does tear up the top of your shaft tube material and will wear on the shaft wood.
So yeah....that is a good reason.
But Me I always like looking at the tips on top, too pick the one I wanted for that particular situation, especially when I played full time, I always had 3 shafts of the same.
One tip I was breaking in, one was broken in and the third was about ready for a new one.
If I ever damaged one, it would not effect the game I was in.