Oh for God's sake. Kaguya having the Byakugan was because Kishimoto wanted to cover his ass. In part 1 he mentioned the Byakugan was the strongest of the eyes techniques or the original one or something like that. Basically he said the Byakugan was better than the Sharingan. However we've seen that's not really the case.
Seriously when are people going to understand the Byakugan is nothing compared to the Sharingan and Rinnegan.
Don't take this comment as a comment against you. It's a comment against the people who think that the Hyuugas and their Byakugan is the strongest thing out there.
In terms of ability of insight, Kakashi said it was better. Also, the link between Byakugan and Shraringan was always meant to be taken as a myth, and not as actual fact.