You wouldn't want to bake without baking paper or sheets, why paint on sketch paper?
The truth is watercolor paper is usually thick and soft, they absorb water much better, in turn, give you the time needed to blend colors, add extra additional layers of paint- all are an important part of art-making.
 
This set of size A2 has 20 sheets, is equivalent to 40 sheets of A3 size paper if you cut them in half, and is equivalent to 80 sheets of A4 size! (A4 is your regular printing/magazine size)
 
There are many kinds of wate