Advantages of locating points on real Z?

[pcmonty1]

It would be nice if Carlson let you pick 2D polylines as proximity breaklines. This was a feature of Land Desktop that I really miss. It's a pain having both 3D and 2D linework of the same features.

[Dent Cermak]

You can. The selection window allows you to use 2d Polys. You can even use lines. Check your options and be sure to also use your crd file for the surface with it and it will generally work. About the same as proximity faults.
It's really no problem having field to finish draw your 3d polys with the rest of the line work. Just have the 3d lines put on layer "srf-flt" (same as in LDD) and once F2F is done, turn off that layer. You only will need that layer when you build your surface. Until then you make it hide.

[J-Mac]

I agree, it's pretty easy to have both 2d & 3d plines created from F2F. I usually set my codes so that 3d plines go to a layer called BREAKLINE. And with the F2F codes, it's pretty easy to set them up so that both 2d & 3d are drawn.

Example:
EOP code creates a 2d pline on EOP layer, and a 3d pline on layer BREAKLINE. And as Dent Cermak wrote, you only keep the 3d layer on for contouring.