I believe, to respond to Matthew, that this argument is definitely important. It is not as you say a non-issue or unimportant what title is used. We need to have clarity because this devotion is extremely important for our times. The main reason the SSPX is attempting to change the name of the devotion in common parlance is to ensure that people will find SSPX materials when they search it on the Internet. By taking over this devotion, the SSPX can make bold moves, like trying to make Marcel Lefebvre the great "Prelate" Mother Mariana prophesied.
This devotion is of equal importance as Fatima, and yet I don't hear anyone here saying the argument over the Third Secret or the Two Sr. Lucy's is a "non-issue". We must be careful not to fight on the enemy's terms...