Imagine that you have several regions with several subassemblies which are using the same Elevation Target (from a profile PRF1).
If you don´t like the profile (PRF1) and create a new profile, then you will have to choose that new profile for every Elevation Target.
So, why not a command to replace a profile (which is being used as Elevation target) for another one?
We wouldn´t choose the profile for Elevation target again.
Another way, is copying all the vertex from the new layout profile to the old profile (PRF1) without removing the old profile.
Perhaps, it could also do this for alignments (horizontal targets) although is not very usual.