The million dollar question for you, the user, is why should I care? By combining their privacy policies into one, it allows Google to take information you have shared with one service, and share it with another. Google says they will “treat you as a single user across all our products, which will mean a simpler, more intuitive Google experience.”
This is all well and good, but it also means that Google can share information about you across various platforms with advertisers. While this creates a more custom advertising experience for the users, it also means better targeted ads and more money for Google.
Of course, Google promises never to sell your information, as they always have, but that doesn’t mean they won’t use your information themselves.
The positive is that the documentation will be easier for users to read and understand. This way you will know exactly what Google is doing with your information across all Google platforms, instead of having to try to piece it together little by little.
Source: Google Blog