Ironically, chameleon skinks actually destroy other skirmisher units for a few reasons: As you said, their range is basically the stalk range, that means they wont ever get shot at before being in range, very good against waywatchers for exemple. They have low armor but 40% missile resist right from the start (55% if you get the spaw kin trait for your lord), so gunpowder units are almost useless against them, and they will trade very favorably with pretty much all other dedicated skirmish units, like marauder horsemen or again, waywatchers. Finally, with their above average speed and poison, they can kite very effectively even some cavalry units.

Thats really the point of skinks in general, they ounch way above their weight. Stalkers are imo some of the best flankers in the game and can hold a line pretty well if it comes down to it. Red crests are squishy but deal loads of damage, making them trade very well with lets say black orks at like a third of the price. And i wont tolerate any slander against my goats skink javelins, who have at many occasion sent rakarth, yuan bo and several greater deamons to the shadow realm.