I am currently writing about the rise of eschatological speculation in the second century BCE. Many texts, especially the Dead Sea Scrolls, are quite allusive: you need to know what the Branch, the Shoot, the Star and so on mean to understand what the text is about. It’s one big intertextual web.
I do not think it was necessary to write in code. At first, I thought it was a bit of a toy for the writing elite, which is not without parallel in ancient literate societies. The Epic of Gilgamesh already contains puns and word plays. But another thought crossed my mind: you can see a similar, highly allusive, kind of poetry at the same time in Alexandria.
If Greek concepts like the soul can find their way to sectarian Jewish religious texts, and if even an anti-Hellenistic text like Maccabees dates events to the Seleucid era, is it possible that a Callimachus influenced Jewish writers?
On a related note: is it too far-fetched to draw a parallel between the use of a dead type of Greek in the Second Sophistic and the use of Hebrew in the Mishna? (Personally, I think this is far-fetched, but perhaps someone knows more.)
Your input is welcome.