Most people clone (make cuttings) for the following reasons....

1, You get an identical copy of the plant it was taken from(If you grow from seed your genetics can vary)

2,They will always be female (as long as you take a cutting from a female plant)

3, Cuttings are quicker to grow from (seeds can add a couple of weeks to the start of your grow).

4, If you make your own cuttings it is very cheap way of getting new plants.

5, It is easy to do

6, there are probabaly more reasons but 5 is enough.