I had to explain the real purpose of the Camera Calibration Profile and that it is not intended as a final develop function but to rather mimic the "Picture Style" from a given camera.
I don't think that's an accurate or good explanation of what 'camera calibration' does or offers.
Whilst it's true that there are profiles that attempt to match different picture styles, camera calibration is much more than just a tool to match JPG output. I regard it as a control for the overall colour response of the camera.
Read back through recent threads in the Color management sections (along with ACR & LR) here and you'll find a lot of serious discussion about what camera profiles do and what methods of building them work best.
For me, having built a profile I like more than the default offerings, I apply that on import. I'd only look at alternatives if I'm having problems getting the look I want, or I know that a specific shoot is likely to be problematical and shot a CC24/QP203 at the time to deal with the anticipated problem with a custom profile.
I think that being something you rarely need to change, putting it at the bottom of the panel makes sense. The changes are usually quite subtle, so getting the tonal state correct through the basic panel is probably the first step to getting a good image before worrying about tiny colour shifts.