A great taming mount with friends! Have one person drive and another shoot tranqs, makes tranqing flying creatures like argies and quetz a breeze, but you can also use this technique to tranq just about anything. Solo, you can hook onto walls such as cliff sides and try to fire from the saddle, although the angle tends to be difficult.
Otherwise, it makes a great "pick up" mount, use it to pick up friends that may have lost their flying mount or otherwise stranded themselves far from home.
However they are quite slow, consider putting a number of points in speed and a few in weight, especially if you want to keep up with fleeing quetz. With enough weight they can become an interesting alternative to an argy.
Once tamed you can get a buddy to fly on the it with you which makes it so much easier to knock out big dinosaurs like rexes and brontos. All you have to do is fly above it and let ur tribe mate shoot darts
Once tamed, the tapejara is a great mount for taming or fighting other creatures. Have yourself or a tribemate fly the tapejara while a passenger in the back seat shoots down at a creature with darts or arrows. The tapejara's unique ability to strafe midair and fly backwards enables the rider to also chase after fleeing creatures such as other tapejara's or other flying creatures. The passenger in the back can also easily attack flying bugs and vultures that may be chasing your bed down.