The answer is quite simple, really.
The Bible belongs to the Church, and it is from her that we receive both its letter (i.e., our ecclesiastical text) and its interpretation (i.e., patristic and liturgical exegesis). Our holy and God-bearing fathers, meditating on those words of Scripture, have seen Christ at every turn. This is the interpretation of Holy Scripture embodied in our prayers, our Services, and indeed our whole Faith. But how can we, the faithful, see Christ in every page of Scripture guided by our holy fathers, if we’re not looking at the same page as they? Yet if our Bibles fail to give us the Church’s text of the Scriptures, we will in fact be looking at a different page, and we’ll see Christ a little (and at times even a lot!) less clearly than our holy fathers did. Gems that, according to them, reveal Christ to us, will have disappeared.
The same is true if our translation is substandard. Think of it as trying to admire a rough diamond as though it were already polished. A questionable or incompetent translation can hide Christ in the pages of Scripture from us; it can darken the image that should shine clearly, and in the worst cases, it can obliterate it entirely.
While a good annotated edition can be helpful in many ways, one must be careful to always remember that the notes are not the inspired Scriptural text; that is, we don’t seek to see Christ in the notes, but in the Biblical text. We must not mistake the means for the end! Consider this: neither the Epistle Book nor the Gospel Book used liturgically in Church have explanatory notes. There such notes become superfluous, because the Scriptural texts are in their true context: that of true worship, and the true faith, “given once for all to the saints” (St Jude 3). This context alone enables us to see Christ clearly in every word of Holy Scripture. Thus, good annotations may be a very helpful aid to our reading, but they cannot substitute for the Scriptural text itself. And again, to the extent that the translation in front of us fails to accurately render the ecclesiastical text of the Scriptures, to that extent it departs from the letter and interpretation that the Church has given us, thus preventing us from accessing that authentic Orthodox approach to Scriptures in which we seek to be immersed.
So, why then must we engage with the utmost care matters of text and translation? So that, when we open the Scriptures, we may have before us all that our fathers and mothers in Christ saw, that they may teach us; and so that we may the see splendor of Christ clearly, and not through darkness. After all, Scriptural reading has little do to with private interpretation, and everything to do with reading in communion with those who, now triumphant, have have gone to their rest before us.