I must chime in once again --
Many years ago, I knew 2 Trads that prayed the "Divine Mercy" prayers after Mass, as part of their Communion thanksgiving.
A forty year old woman with 8 kids, and a young single man about 22 years old.
They ended up committing adultery with each other. I wonder if the emphasis on God's mercy pushed them over the edge, to allow them to commit such a sin?
If they had been meditating on the Passion, the Sacred Heart of Jesus (wounded for our sins) -- maybe it wouldn't have happened? Who knows.
Second example: an otherwise conservative group in the local area, "The Mission of Divine Mercy". They promoted John Paul II and Medjugorje. Oh, and their 1 hour Adoration of the Blessed Sacrament began to be corrupted by "speaking in tongues". I have this from first-hand reports.
All I know is -- there is no good fruit from this novel, UN-traditional devotion, calculated to overwrite true devotion to the Sacred Heart of Jesus. Would I go so far as to say it's demonic? Maybe.