So to compare different versions of a sutta can help identifying what was probably the earlier/earliest version. We make out the purpose and agenda of the text and of the alteration.
But obviously only few suttas are textually independent and there are numerous trans-sutta connections. Conversion formulas, question formulas, politeness formulas, winning-a-debate formulas, hesitation formulas, criticism formulas, astonishment formulas, invitation formulas, enlightenment formulas, etc.
Beyond analyzing and understanding a single sutta the analysis of such formulas can show us the purpose and agenda of such text modules which, per definition, must be older than the individual suttas which include the modules/formulas.
I find this approach very valuable. And add the approach/question: What are examples of suttas which are free of trans-sutta structural elements? They could represent individual voices we could really treat as individual suttas, standing on their own. Maybe we find these only in verse suttas, but maybe also in some prose. We should approach the interpretation of such suttas differently.