Name[Field1, Field2, ...] is not an opaque data type. Maybe you can give me an idiomatic example of how to build a binary tree, for example? Or maybe something more complicated like a doubly linked list?

I do not write Mathematica code, but most code I've seen usually ends up being this mess of functions. I'll give you that maybe the code I've seen has just been bad, so we can ignore my point there.