Board Thread:Naruto Discussions/@comment-29393962-20161111215453/@comment-734582-20170118115230

Elveonora wrote: Why do you think those are TBB instead of TSB? The avatar seems to be using them in melee range, that would be a weird application of TBB Rasengan has a melee application, which is weird as well...

But the practical reason? Bijudama are reasonably easy to obtain for a person whereas TSB's arent. And it's especially easy if he really did have Wood Release and was the progenitor of the Uzumaki.

EDIT: i just realized... is there anything that said that TBB's are biju-only? I mean only a Biju has the kind of chakra and stupidity to use such a technique, but what would prevent Ashura from learning TBB's and using it? or what prevents anyone from learning it? (other than stupendous chakra requirements and being a really inefficient jutsu)