Argies can be used to carry many dinosaurs into taming pens that are too hard to tame in the wild with other dinosaurs that might interfere with the taming. Pump stamina and weight for a great transporter.
Getting a massive TLC update in March 2018. The saddle will act as a mobile smithy, Argentavis will be able to carry with Talons as well as with its beak, reduced carry weight on obsidian and a few other unannounced resources (similar to the mammoth and wood), and will also gain a Rapid HP Regen upon eating (likely from devouring corpses and not specifically food from inventory). Like so people can see!