Yes, it was. Square Enix is currently making mobile phone games that look better than some PlayStation 2 games. They're at no disadvantage to produce high-quality graphics, whether they're 2D or 3D.
Then I can only think they wanted the game to be appealing for old nostalgic players. There's no other explanation I could think of. Which is too bad, because I highly appreciated the updated graphics in, say, the 20th anniversary FF's.