“For reality is one with the Father and the Son, and the Holy Spirit blesses the real world in Their Name.” (ACIM, T-12.VI.4)
Jesus does not get away from the Trinity, a traditional Christian concept. He does allude here to the primacy of the Holy Spirit in our experience.
Jesus thinks that trying to approach God, before some of the fear of the ego has been abandoned, would be more traumatic than beatific. I think that this is the primary reason that he emphasizes the Holy Spirit. Our Comforter, the Holy Spirit, does not scare us as our own minds might allow us to be afraid of God. The Holy Spirit, we are told by Jesus, mediates between God and us, opening the way to a more direct approach, which we find in the final third of the Workbook of A Course in Miracles.
The Holy Spirit, as the mediator, blesses the real world and accustoms us to experiencing that real world. It is the world that Love shows us, love and loving thoughts and loving actions.