This posture is like Samasthiti for seated postures.
After a vinyasa in the seated posture, come back to Dandasana will allow you to create stillness in the practice, come back to your breathing and Bandhas and build up the foundation for the next posture
The benefits of Dandasana are.
1. Help you to lengthen and strengthen the muscles in the lower back
2. Will train you in how to use your legs in order to lengthen your back when you seat
3. Build up concentration
4. Prepare your body for the next set of postures
5. This posture will constantly remind you that in seated postures your body have to be engage.
6. Because gravity will be working more intensely on you in seated postures. Activate the legs, pelvic floor and core will help you to lift up against this donward force. By doing this in each Dandasana you will be able to train your body in how to engage the muscles in order to seat
At the beginning the posture can be really challenging specially if your hamstring are tight, in this case feel free to bend the knees or seat in something higher will allow you to tilt the hips forward, this will help you to seat with your back straight without feeling pain in the lower back
Let us know how this work on you
Ricardo and Joy