why are terms like 'Biblical Greek' and 'NT Greek' still current?
Er...sorry to answer as a newb, but perhaps for emphasis on the peculiarities to those texts themselves? (such as theological significances, allusions in them, similar forms of expression, interdependence on knowing one or another text for another, e.g. lots of old testament background for new testament stuff...) That's all hypothesis, of course; as a new guy I am not interested merely in learning just from the LXX/NT but from a wider corpus as well, to have a much larger grasp of the language in play around that time, before, and beyond.
At the time I was supposed to start some studies at the CCSI place (see my own intro), the instructor there was actually working on very early Byzantine texts that have never before been translated, and were apparently unknown (among some that were known, but were mis-attributed, probably to keep them from being destroyed as works of a heretic or something like that): dang I wish I could have done studies at that time, to learn from the guy. : (
J. Bradley Bulsterbaum.