If you put saddle on them and run of a cliff they will
glide

While their stats tend to be average they are super fun mounts. I love that they glide. Try and see for yourself.

this is the fastest creature I have ever tamed ussally I would use a sarco but now I think I might use the terror bird for on land travel

It can flap its wing and glide kinda like an archaeopteryx and you can cover large areas like ravines and gorges on your terror bird, level up stamina in order to glide for longer.

100% a scout. Don't even try to get in fights with it. 600 stamina is good enough to fly from top of volcano to ground. I like 200+ speed. It's mostly just a fun mount.