I'm curious about when you would want to use a "Sketch Equation" versus a "regular" equation.

The Solidworks helps says:

Sketch equations differ from equations used in parts and assemblies. When you add or edit an equation to an active sketch, geometric relations between sketch entities are automatically applied, related equations are solved, and the sketch automatically updates. With equations used in parts and assemblies, the model does not update until you rebuild.

From this I gather that the solver treats the two types of equations differently.

Is there any reason to prefer to use sketch equations when you can? It seems to me that having your model definition spread out over too many places is a recipe for being confused.

Is there any benefit for one type versus another when you are working with a rolled-back model? One of my annoyances with equations in Solidworks is that if your model is rolled back, new equations are added to the end of the equation list, so you can get out-of-order solve errors. The same thing happens if you drag features up or down in the tree. As far as I can tell, the history order in the equations versus feature manager isn't automatically synchronized.