I think that even if using those you still have to find out the value that the vector should be which means either setting up dummy nodes and calling lookat and getH() (and cos and sin and adjustments for them) or transforming the point as I am, then converting it into a normalized vector, then calling the function, then figuring out which direction to go as it returns an unsigned angle according to the docs. The question boils down to is atan2 faster or slower than angleDeg/angleRad although I believe there is slightly more overhead in that more things need to be created (vectors and such) for angleDeg.
In the end it does not matter as these are fast enough; I am calling them 50-60 times a frame and not noticing any slowdown (although it is locked to 60 frames a second…) I use them to compute hpr intervals constantly.