Time that wouldn't have been needed if Juha had went Yama himself from the start.Royd bought some time so we can say that he helped him, plus just like the guy above said its impossible to beat Yamamoto with bankai, he had to stole bankai to defeat Yamamoto..U_U
And it doesn't matter if it's impossible to defeat Yama without stealing his Bankai.
Stealing Bankai's is a Quincy ability, so it's still a solo with no diff.