Why do people say that the clay block works better than the clay bar?

How does the magic clay block work? 
Why is magic clay block  easier to use? 
because design a high quality clay on the clay block top; 
the clay can remove almost contaminants from car body, car paints, car glasses. 
and the sponge can supply water when the clay touch the surface of paints or glasses. 
so, it is easy to use, different like clay bar. moving and watering in the same times of washing process.  
Why does the clay block work better than clay bar?  
1) the clay block in washing process is easier to use than clay bar; 
2) the clay on the sponge of clay block,  it is harder than clay bar, it is not easy to stick stants or dirty on the  clay.  so, the clay block also can avoid bigger dirty or stand stick on the clay to scratch car paint.
3) and the sponge also can wash car body first, than use the clay side to remove contaminants. it is not easy but safe for the car washing process.