The Canvas component is the starting point for anything based on UIX. It provides the bounds of the UI and controls how users can interact with it.
When updating certain things on the canvas, you may need to duplicate the entire Slot to get the canvas (and any other UIX elements and slots under that canvas) to work again. The specifics for this canvas component that may need to force recalculation are as follows:
DefaultCulling: Especially for rendering the back side of the canvas.
If true, integrating this asset (e.g. processing procedural assets) gets higher priority than assets with this flag off. An example is user laser procedural meshes.
This component is needed for UIX, without it, your other components that relay on UIX, canvas, elements, and rects will not work as expected. Using a canvas not only organizes your other components, it renders them and makes them usable and intractable.
Examples
Here is a video from ProbablePrime's tutorial on canvases: