I think it is mainly used as a binder, so recipes that use non-gluten flour, like coconut or almond, often use it. Recipes without it often use eggs to bind, but the eggy taste isn't always good. Other things that help binding and rising in baking are flaxseed and chia. I used flaxseed to make low carb muffins once and they came out well but they also had a high egg content.
I've been looking at vital wheat gluten, and have just bought some from Amazon. When I have time, I'll experiment with some recipes because I really would like to see if there's something low-carb I can make to stop me lapsing with bread products.