Standing poses work on Muladhara (Root Chakra) and help us to feel grounded, connected to the Earthly plane, strong and stable. At the same time, they help to create space in the hamstrings and hips, which helps us to build good posture.
This short sequence can be done whenever you're warm - after a workout, or maybe after a few rounds of Surya Namaskar or Chandra Namaskar.