The executive has actually revealed the reason why the China based manufacturer made this decision. According to Yu, Huawei wanted to emphasize the user experience with the Honor 3X instead of the specs. He pointed out that there is not much difference in the viewing experience between the 1080p and 720p screens and added that the latter resolution glass consumes 20% less power than the FHD screen. Additionally, the panel being used by Huawei is produced with the Low Temperature Poly-Silicon technology. Huawei says that this process allows users to have a smoother scrolling experience.
So if you're curious, that is the explanation from Huawei's top executive. If you're not happy about the reason why Huawei has decided to use the 720 x 1280 glass on the phone, consider this. When the battery on your Huawei Honor 3X is almost dead, and you need to make a very important call, you'll be glad that Huawei decided to go in the direction that it did.
Thanks, Anonymous Tipster!
source: MyDrivers (translated) via GSMInsider