No. People need water and food and air, shelter and money is also a nice thing to support survival. No one 'needs' any material possession. Though if the answer is would I like to buy one. Still no, and I have a phone, why would a smart watch be of any use?
While the technology does look interesting and it may become similar to cell phones in the future where everybody has one, no at this point currently I don't need one. They would not serve a useful purpose for me. Everything I need I have on my phone which I keep in my pocket. A watch may make it easier but only be a fraction of a second.
Google-powered smartwatch depends on its user entirely. It is a great device to have and it makes life a lot more convenient and easy. It is an additional item that one can add to make their lives easier. The smart phone is good enough, but with a smartwatch, one can do a bit more and make it easier to answer calls or texts while on the go.
The smartwatch is just another technological device that is created to make technology seem to be advancing when it really is not. Everyone carries their smartphone with them these days, there is no point in having an additional device that does all the same things.
There is also a question of security, if the smartwatch was created to make things easier for the user, does it also make it easier for others to read their messages because it shows up on a big watch?
No, you don't need a Google smartwatch as it is still too early for smartwatches to be an important device like tablets or smartphones. Manufactures should work harder to provide useful and creative features that can introduce a technological revolution, and that hasn't happened yet. I believe that getting a smartwatch right now is a waste of money.