Yes and no. It makes sense that there is no 100% pure scripture, because physical evidence shows that to be so. It makes no sense to assume that it is "suffciently accurate to serve its' purpose" because there is no objective evidence to come to that conclusion except by blind faith (in which case you can't appeal to reason).
The other reason why it makes no sense is what exactly constitutes "sufficient" and how does one measure it in this case?
And there was no Hebrew Scripture? What makes the Septuagint your superior, or only, source?
Alexandrian and other (Greek-speaking) Jews were also "real" Hebrews. What makes Palestinian (Armenian-speaking) Jews "more" Jewish? Why does one Jewish sect (i.e. the Pharisaical Palestinian Jews) have the monopoly on what is "authentic Jewish" scripture?
Even in Israel today the state recognizes two equal but different rabbinates, one Ashkenazi and the other one Sephardic. They even recognize the few hundred Samaritans as "real Jews" as well.
Are we to say the Greek-speaking Jews or the Essenes or the Sadducees were not "real" Jews and their scriptures, which differed from what the Pharisaical version and what the West arrogantly calls "Hebrew" scripture, were not equally Jewish?
What makes the Septuagint more important (not necessarily superior on an absolute scale) for Christians is that the Septuagint is the Jewish Bible quoted in Christian scriptures. Clearly, Christian dogma can only be derived form that version or else there is no consistency.
Armenian-speaking should read Aramaic-speaking
This is a very interesting statement to me because you seem to presuppose a dichotomy between faith and reason, protraying faith as irrational, blind, or absurd, and opposed to reason. But faith is not only thoroughly reasonable, it is the very foundation of reason because reason itself would be impossible without it.
All that is necessary to illustrate that faith is the precondition of reason is to ask you, do you have evidence for everything that you believe? How would that even be possible for a finite creature? Not even skeptics like you can proceed intellectually without certain assumptions or prove everything you believe by independent demonstration.
If you are implying that Christianity is irrational simply on the basis that it allows for something to be accepted without independent demonstration, then you end up refuting yourself because you inconsistently require something of Christian believers that you do not and cannot live up to yourself. If you required objective evidence for everything that you believe it would make knowledge of anything whatsoever impossible for a finite being, which ironically ends up being very unreasonable.
Moreover, your claim that there is no objective evidence really entails a claim of omniscience, since you would have to have had to have searched everywhere and looked at all things at the same time to be able to make the claim, at least according to a presupposed standard of not believing anything unless there is independent, objective evidence for it.
If God subsists (and He does) and has revealed Himself in His Word then we are entitled to believe Him on His authority, His authority being proper justification and ground for our belief that His Word is sufficient, as it claims.
The bottom line is that to criticize the Christian's irrational "faith" on the grounds that "there is no objective evidence" for it is itself nothing more than an expression of a different religious faith - a faith in which you presume the ultimate authority and self-sufficiency of your own finite human mind instead of the ultimate authority and self-sufficiency of the infinite God, a presumption that cannot help but result in futility, arbitrariness and irrationality.
Cordially,