My argument isn't that the LXX was divinely inspired, but rather that it gives insight into the meaning and understanding of the Hebrew text, particularly with regards to it's grammar, syntax and idioms.
This "man-made translation" that you eschew/criticize of having "little value" was used and quoted repeatedly by the NT writers (some 90 times, verbatim if memory serves), and who were divinely inspired by the Holy Spirit to do so.
A sample of these quotes that you assert as having "little-value", are found here:
Septuagint Quotes in the New Testament
I find it amazing that you, living some 2,300 years after the LXX was first translated from the Hebrew, believe that you possess more knowledge, understanding and insight into the Hebrew text, as pertaining to it's vocabulary, grammar and syntax, than the 70 who translated it into Greek.
BGTF, you simply cannot be taken seriously, and I hope you realize this.
IF, as some who are ignorant of the FACTS, like you, claim that the LXX was used in the New Testament, then either the LXX is EQUALLY Inspired by the Holy Spirit, as the Original Hebrew Old Testament is; or, the New Testament Writers used a UNINSPIRED man-made TRANSLATION, to quote from, which means that the New Testament is not fully Inspired by God the Holy Spirit. Can you understand the HUGE problems what this means?
You said, "My argument isn't that the LXX was divinely inspired, but rather that it gives insight into the meaning and understanding of the Hebrew text, particularly with regards to it's grammar, syntax and idioms"
Let me show how you are WRONG
Exodus 3:14 in the Hebrew, "’ehəyeh ’ăšer ’ehəyeh"
The LXX reads, "ἐγώ εἰμι ὁ ὤν", literally, "I am the Eternal One". It does not correspond to the Hebrew, which should read in Greek, "ἐγώ εἰμι ο ἐγώ εἰμι". What the LXX has done, is to give the SENSE of what the Hebrew is, and not the literal reading.