I would not agree with your assessment for a few reasons…
Arcing/Bracketing are quite useful with smaller portions - anything with 2 or more propositions. I have often pulled just a verse or two out of a larger arc simply to highlight a single logical relationship.
Phrasing can be useful for larger passages. In my own experience, I have regularly phrased whole chapters, in fact this is often the first step in my sermon preparation. (My phrase often gets tweaked as my study progresses.)
I agree that Arcing/Bracketing does work well with a large, extended passage of multiple chapters. This is called macro-arcing and requires that you condense closely related propositions into single units, otherwise the arc gets unwieldy and the larger thought flow lost in the details. I’ve not tried to Phrase such a long passage, but suspect it can be done in the same manner– that is, by condensing closely knit phrases together.
The main difference I see is that Phrasing emphasizes the grammatical relationships, while Arcing/Bracketing emphasizes the logical relationships. I say, “emphasize,” because, of course, grammar and logic are closely related.