Backing up your contacts with gmail is incredibly handy, for one, you will never lose your contacts even if you lose all your devices. For two, any built in Android app can access your contacts so you can just enter names instead of having to remember numbers and emails. I can log into any computer or device and access all my music, files, contacts, calendars, emails, pictures, everything.
If you don't want Google to have your contacts you really shouldn't use a phone that's made by Google and runs Google's mobile operating system, where you use a Google account to do pretty much everything.
I don't mean that to be snarky. The way Google handles login and contacts/calendar is incredibly robust. The nature of Google's ecosystem is two way. Their products work well when you give them information. Google now for example.
However, if you have privacy concerns you may be better off using either a custom ROM, a different OS, or not a smartphone.
Posted via Android Central App