I don't think you are missing anything, the animation control in Twinmotion is severely lacking, almost to non existent unfortunately.
Ideally we would have:
- Controls for ease in or out during movement.
- Transition matching between clips.
- Animation curves graph for editing animation timing, length and ease in/out.
- Dope sheet for animation keyframe timing.
- Decoupled camera object from views to animate without having to move the camera from a first person view.
- Decouple the camera animation from the current "add keyframe" system.
- Camera roll functionality.
etc. There are probably other things as well but this is from the top of my head.
Currently we hesitate a lot to use animated sequences in Twinmotion due to the unpredictable nature of it.
Unless we use like you say from the examples , cut together short simple sequences.
I'm hoping there is currently ongoing work to revamp the animation system in Twinmotion, it really needs improvement.
Improving these tools would make Twinmotion a much stronger product.