Answer: 
The reason is that you can also sit on Walkstool without extending the telescopic legs. This gives a perfect position for professional users like electricians, installers and service technicians et c, when working in low positions from time to time. They have in general big problems with their knees and Walkstool could reduce the pressure on the knees with up to 70% compared with using knee pads (which not everyone is doing). They can also sit on Walkstool with extended legs when working in medium height instead of having one knee in the ground or bend their back. For people being out on picnic, painting fences etc in low positions, working with their motor bike or in garden, Walkstool could be perfect. Try yourself to sit in low position. After some seconds you will find the balance and notice how nice it feels.