The Marghariba guard and lizard pilots DO serve a purpose (since you can dismount from the TAGs in game, and remount) - I use my Lizard pilot model now and then - not for any VP purpose, since if the TAG dies, they can't prevent the opponent scoring Vp for you. But to show dismounted pilot where needed (forcibly ejected or otherwise).
The O-yoroi and Tech-bee less so (those are definitely more pin-up collector/painter model).