The only spear-chuckers (I can't spell the other word) in my force are on my Speerwurf and I use them similarly to DarkKnight. For 50-100 points, I can put an agile, hard to hit unit on the board that will draw the enemies attention far beyond the unit's actual damage potential. I also believe that using the Speerwurf, as opposed to larger models, makes more sense. A full unit of 4 can throw an impressive 10 AD at RB 2, which may not crack a dread, but has good odds against a battleship, and sets up the target for the really big AD pools from the squadrons of larger ships. Heck, a 1-2 punch from 4 Speerwurfs and then 5 Arminius is just nasty and can be accomplished early in the game given their speed.