$$$ isn't it? If its "Christian," why is it so expensive? I find that so much religion today and in the USA especially is based on exploiting the gullible for profit. Heck even the worldwide 2nd hand religious book market has been monopolized by the USA for financial gain. Would Jesus have bought this stuff? Could he have afforded it? I doubt it. I don't know about NICOT but so much "Christian Scholarship" today is perfect dross, without a doubt.
I've never heard of them, to be honest. I prefer the much older and time-tested writings of the Church Fathers on this issue (much of which is freely available online...)
There are various gifts of the spirit among which is teaching. Some teachers might write.
On the other hand some academics don't necessarily know God and have saving faith so it takes discernment.
Some teachers are able to make their material available free or at low cost. For the 3rd world I think that's a really good thing.