My question is, why did SW code the system to add coincident relationships to the centers of arcs /circles instead of concentric ? Is there some deep insight that might simplify my workflow?

As a specific workflow example, I use the Hole Wizard a lot. I frequently use it to make holes in cover plates. I can then use the resulting feature to create an assembly pattern of hardware (screws, for example).

While adding points to the positioning sketch for the Hole Wizard, there is a strong temptation to snap the points at the centerpoints that appear when "tickling" other components/features in the assembly.

If I do that, then the resulting sketch relationship for the new sketch point is "coincident", not "concentric" as one might expect.

I've encountererd several situations where subsequent model edits cause such automatically created conincident relationships not to rebuild properly. The only solution I've found is to delete the coincident relationships and replace them with concentric relationships.

My habit now is to drop positioning points to avoid automatic relationships. I then manually add the concentric relationships until the sketch is fully defined. By doing this, I've had fewer rebuild problems down the road.

It would be much more efficient to be able to trust the automatic sketch relationships.