The LTS releases get a kernel upgrade and graphics libraries every six months or so. So, you get newer hardware support even if you stay at 16.04.

There is a new such update for 16.04 at the end of this month. It is the 16.04.02 update.

While LTS has benefits, there are reasons to running the latest version you can get. Especially with new hardware, there are going to be updates to the relevant drivers which can improve the battery life a lot.

Over the first year after I bought the older X1, my battery life got an extra hour or so because of i915 module improvements. (I was following latest arch kernels)