As an opponent, remember that even if you don't move your officer and the wormpiles tries to reach her, it will likely take 4 turns for it to succeed, and to inflict her 3 ridiculous points of damage on turn 5!
On turn five, three wounds may very easily make the difference between a living and a dead officer
I'm just thinking out loud, but that could be one of the idea behind the stats and abilities of that model: it's so slow you might not bother dealing with it, but when you get to the end of the game, that thing is getting inexorably closer, and your officer is not in such a good shape any longer, you'll wish you had dealt with it earlier on.