The creative journey for many an artist begins with an inner dialogue, a conflict, questioning. A voice in the inquisitive mind doubts existing rules and boundaries while challenging the artist to redefine and broaden them.
In traditional Japanese pottery, few succeed in making any real "progress" with age-old forms. There's not much improvement one can make to a chawan (tea bowl) or chaire (tea caddy) per se.
Yet, if you happen to be a ceramic artist more interested in sculptural forms in a semi-avant-garde realm, it's much easier to find one's own answer to that questioning voice. The rules are nonexistent and it's a wider road.