It has the least abilities and development that's for sure. I don't think it is weak though... The shinobi that have the Byakugan are all lame minus Neji. Imagine if a shinobi like Itachi or someone of equal caliber had the Byakugan plus his arsenal of jutsu. The Hyuuga clan are a waste of the doujutsu if you ask me because they have so few attacks. Taijutsu is really it but it's pointless. They have eyes that can track long distances but can only truly fight close range. They might as well put the Byakugan in Kakashi's dog unit.
What exactly would you do with a doujutsu that allows you to see into another persons chakra network? How would that benefit Itachi who could already see chakra flow with his sharingan? It takes MASSIVE amounts of training to hone chakra control to their extent. Also, the Byakugan is wasted in the Hyuuga? They basically have the most deadliest taijutsu in the universe. For any Hyuuga, a single hit anywhere can cause MAJOR damage to the body, even against the toughest of people like the raikages. Advanced users can shut down their opponents chakra network, leaving them unable to use any form of jutsu whatsoever. The most elite have techniques that can kill an opponent in 1 hit to the heart and can do so with near imperceptible handspeed(64 palms), and they also have skills that make it hell just to land a hit on them(rotation, arguably the strongest absolute defense in the manga at its most powerful) Their ability to see all around them and long range can let them see an opponents traps and moves while their opponent is unaware, giving them a certain advantage in battle that a rinnegan or sharingan user doesn't.
So outside of that, the most anyone could make use of it is to use it as a sensory device as already shown with Ao. Unless you have the chakra control training to use it otherwise, there is practically NO benefit to anyone else when the sharingan and rinnegan offer more offensive power and are more suited to people using ninujutsu.
