But this also means that Kaguya's descenedents eventually managed to breed their genes into the entire population of the ninja world. Chakra isn't just something a few special people have, it's something that everyone NEEDS in order to live. Their bodies are dependent on it even if they can't properly use it.
This also brings into question how bloodline traits work. I'm going to guess it's something like the Kouga Ninja Scrolls, were people were bred for certain abilities. Which would mean that the Byakugan and the Sharingan, being exclusive to their clans, are proof of how interbred those clans clans are.
Chakra is basically soul while ninjutsu is pretty much magic.
And all being have chakra aka soul or else the cat Will not get ET. Or how frog capable to perform water magic attack.
Bloodline trait is Kishi after thought. He just make it in wave arc. That's why almost all bloodline limit are double elemental mix while there are only 3 non element bloodline limit such as sharingan, byakugan, and Kaguya clan Bone. Rinnegan itself is just sharingan evolution.
I think sharingan should give the body increase streght when activate. They're really weak when i think about it. Kinda like kurapika Scarlett eye.