How content helps for getting better ranking in Google?

[brian]

Extremely unique content might help. But otherwise not.

I have seen plenty of sites which have content value equal to zero but they rank well because their link profile is very strong.

I couldn't agree more.

People may say that content is the king. But its totally wrong. Google may have made a lot of changes lately in its algorithm. But still what we are viewing is that sites which have good links from relevant high authority sites are not getting any fluctuations in their SERP's no matter what.