AoS Saurus Warriors 30x vs 10x3 (Sunclaw)

How does model count to claim objectives change things? A big block of 30+ Sauruses, while expensive, can very easily hold down an objective and deny it for quite some time. With skinks you get a -30 refund for the less point of armor (or no armor) but in exchange you pay +10 points for the 8" - 16" ranged shots (not to mention less melee attacks and less expected damage). I don't feel like that is a really good trade off.

As a maneuver unit I can see why a big block is bad.

 

I think part of the thought process is that a big scary horde is basically a walking target for shooting and magic. Not to say that's a bad thing. Sometimes it's nice to have that distraction to draw fire away from more important units. The mobility isn't too big of an issue, you don't have to move in a giant block formation.
But nobody wants to waste their shots on a small unit of skinks or saurus warriors, so while they won't hold an objective for long when challenged, they have a better chance of surviving until that last turn. That and battle shock isn't as effective against small units. If he takes out 12 from your big horde in a round you're losing d6 more.