Natural languages are sequential. Everything depends implicitly on anything that has been said before, and which builds up a context. Von Neumann computers and traditional computing languages are based upon this model of language. Rhetorics are an early attempt to tackle this (predating philosophy!).
The structure is part of the contents: it tends to explicit the otherwise implicit dependencies.
The concept of stream (more general that this of transaction, or of function in structured programming) is related.