Every single Christian is in actual union with Christ. Even though every Christian can claim actual union with Christ and all that he is and all that he has, there is a difference between actual union and operational union. If you buy a new smartphone and it possesses all the equipment necessary to do what a smartphone can do, but it is not operational, then what good does it do to have the new smartphone except to look at it and talk about it. Jesus did not come to live inside of us in all of his glory just to sit dormant in all his potential so that we could point to Him talk about Him. Jesus came to live inside of us to be operational; living His resurrection life in and through us with all of His power released. He came to show the world who He is by demonstrating His life through our humanity. The church, as the Body of Christ, is supposed to be Jesus on display.
We have this treasure (the limitless life and power of the risen Christ) in our frail earthen vessels so that the greatness of the power by which we function will be of God and not from ourselves. To be a new creation is gloriously more than a new position. It is a new experience. It is literally being born again and becoming a whole new self; a self through which Christ now lives as our very life. This is both the promise and the adventure of the Christian life. Being daily set free from our limitations by the limitless life of the risen Lord Jesus is the normal Christian life.