The full quote is:
"As you might expect, economics played a big role in our choice of the Airbus A320 family for JetStar," said Qantas chief executive Geoff Dixon.
"But we also liked the competitive edge and its modern design and more comfortable cabin will give us in the low-cost arena
Looking at the full quote I think he is talking from the LCC perspective in that the A320 has the more comfortabel cabin in the LCC configuration.