If God and Christ are in reality not of the same substance, then teaching that they are obscures the scriptures and keeps people from becoming like Jesus.
If God and Christ are in reality of the same substance, then teaching that they are not obscures the scriptures and keeps people from becoming like God.
Let me likewise keep it simple:
Genesis 3:5
"For God knows that when you eat of it your eyes will be opened, and you will be like God, knowing good and evil."
Becoming like GOD is not very high on our adgenda.
22 ¶ And the LORD God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:For once, Satan told the truth. Ya just can't trust a liar to even lie reliably, can you.