On an ergonomic chair, you are seated conventionally, your weight supported albeit in the healthiest, most comfortable way. The height is adjustable, allowing your feet to be flat on the floor as the backrest supports your lumbar region. On a standing stool, you are 'perched' actively, making you more conscious of your working position and able to gently shift your body to the most comfortable position rather than sitting rigidly in a chair.
Stools promote dynamic movement and an upright posture, which is beneficial for short-term use. However, it's important to recognize that they may not be as ergonomic as chairs for longer periods.
