@Ganteng097 Ratings are determined almost purely by the question of how difficult they are to contain.
If you lock it in a box, leave it alone, and nothing bad will happen, then it's probably Safe.
If you lock it in a box, leave it alone, and you're not entirely sure what will happen, then it's probably Euclid.
If you lock it in a box, leave it alone, and it easily escapes, then it's probably Keter.
If it
is the box, then it's probably Thaumiel.
In the case of SCP-1471, it is an app already on the store (thus cannot be contained without active effort) connected to an entity very few can interact with (only long term exposure to the app allows interaction) and so far nothing's happened beyond people being creeped out by it.