This was a much discussed feature when the first pre-releases came out and even before when the first demos at Maker Faire NY showed engrave from bottom to top.
There are use cases where changing the direction might be helpful. My take on it is that the exhaust system and air assist are tied into this, as is the design of the case. The head camera and smoke might enter into it. Lots of pros and cons.
As it is now, you are not missing a hidden feature. It seems that the current functionality is what is to be expected, until something different is announced.
Here is an old topic that has lots of things to consider: