When someone (i.e. an academic), who knows nothing of Henry, asks me 'why Henry?' my usual response is: Duns Scotus (whom you know about) got a lot of interesting ideas from Henry. Or, if one knows about Descartes, I might say, 'did you ever wonder where the term 'objective being' came from? So far as I know, there are no antecedents to Henry's using it.' It might be that Henry made it up in the midst of his interaction with medieval Arabic philosophers, e.g., Averroes. The place (so far as I am aware) where Henry first uses it is in his gloss of a quotation from Averroes's Commentary on Aristotle's De Anima 3. This is a hypothesis; Henry may have used it before this, or he may have borrowed it from someone else. If one searches the database of Thomas Aquinas, the term 'obiective' is nowhere to be found. If one looks through Henry's writings, it abounds. If one looks at Scotus and his followers, it also abounds. One might posit the historical conjecture that Henry invents it. This is different than saying that Henry invents the concept of 'objective being', rather it is to say that he gives a lasting name to it.
There is a decent amount of literature on Henry of Ghent in languages other than English. It seems that only in the last 30-40 years or so has there been anything in English. You might say that now is the time when Henry is receiving the most interest in the English speaking world, both because of the critical editions that have been produced since the 1970s, but also because of various scholars that have written articles on Henry in comparison to other scholastic philosophers. Even more, there are now four published books (that I am aware of), in English, entirely dedicated to Henry (excluding any PhD. thesis).
(1) Henry of Ghent: Proceedings of the International Colloquium on the Occasion of the 700th Anniversary of his Death (1293). Edited by W. Vanhamel. Leuven: Leuven University Press, 1996.
(2) Henry of Ghent and the Transformation of Scholastic Thought; Studies in Memory of Jos Decorte.