From ESOUI Wiki
Interactions are a state of being in which the player-character is engaged with some object in the game world. Interactions typically remove the player's control of their character and are tied to some menu.
As an example, when the player activates a crafting station in the world, they enter an interaction with it. During that interaction, the player loses control of their character, and menus and add-ons are allowed to call functions to craft, deconstruct, research, improve, and refine items. The game doesn't care what state any menus are in; for example, an add-on can deconstruct items at any time during a crafting interaction, even if the "deconstruction" submenu isn't visible. When the player takes some action to close the menu, the menu calls EndInteraction(INTERACTION_CRAFT) to end the crafting interaction, such that the player regains the ability to move and loses the ability to perform crafting functions.