Board Thread:Wiki Discussions/@comment-1514283-20140911040828/@comment-4912646-20140914200825

Since I don't think it has been pointed out, we were told the black substance can only take on another form for a limited time before returning to sphere form. So it's not as though a bunch of spheres is simply the preferred form of the users (like Gaara choosing to shape his sand into a gourd), it is actually the default form. Even if you do consider the altered shapes to be separate techniques worthy of their own articles (which I personally see as unnecessary), at the very least they are all still derived techniques from the spherical form (Truth-Seeking Ball).