In his proof that all odd numbers greater than 1 are the sum of at most 5 primes, Terence Tao uses one large major arc around 0 rather than small ones around the rationals, which I am more accustomed to seeing. What are the advantages of using such a major arc?

Here is the paper: http://arxiv.org/pdf/1201.6656.pdf

I have also posted this on math.SE here: https://math.stackexchange.com/questions/785782/major-arcs-in-the-proof-that-every-odd-number-is-the-sum-of-at-most-5-primes