By default, yes. But it is an optional... option!

Of course Google do evil; they are currently causing me headaches with their Google Account stuff and I cannot use an Android powered handset without one. So I use my gvee.co.uk address and welp; not everything works as well as I'd like sometimes - I have to maintain two accounts for certain things.

For example my gvee.co.uk Google Account cannot sign up for Analytics, so I must use my old gmail one. PITA.