Seated Forward Bend is an excellent posture to stretch the back of the thighs (hamstrings) and the glutes. It can easily be practiced by itself.
Outside of my yoga practice, I sometimes like to stretch my body. And this asana is one of my favorite for this. I like to take extra opportunities to work on getting more flexibility in my hamstrings. Runners, cyclists, hikers or other sports enthusiasts who have tight hamstrings would definitely benefit from a regular use of this posture.
Seated Forward Bend is a calming posture. It helps to calm the mind and to slow the breath down. This can contribute to a better sleep or simply lead you toward a nice and calm time before falling asleep, if you practice it before going to bed.
On each inhale, lift the chest up slightly and lengthen the spine to increase the fold at the hips. Then exhale and release down.