None of the mast step pins are designed to keep the mast in column while raising. The Hobie pins and plates are nice in that the mast can be pointed straight forward instead of rotated 90 degrees but are not strong enough to keep the mast from going side to side either. I had a 5.2 that didn't originally have a captive system for keeping the mast base on the ball during stepping and it was a PITA.

The reason that we remove the pin while sailing is a safety thing. Imagine that a shroud or forestay were to fail and the mast came down. If the pin was in the mast base, you've just built a 26' nut cracker - and you're the nut. If the mast base is free the rig comes down rather gently and slowly (not that I've experienced this personally, but I've seen it happen) without damaging anything.