Author here. The example given is slightly contrived. A more realistic example involves large polygons that you zoom “inside” or locked elements overlaying active ones. But I had to try to give an example without a ton of context.
There are some more interesting but less easy to explain to a broad audience examples.
One is having “nearest the pointer” hovering logic rather than rectangles or circles overlaying each other.
Another is hovering line segments and the projecting the nearest hovered point onto the line. That was approximated with SVGs before and was just kind of a bug.
Another example is allowing some “wiggle room” for touching elements without having to render SVGs multiple times with transparent elements and stuff like that.
There are some more interesting but less easy to explain to a broad audience examples.
One is having “nearest the pointer” hovering logic rather than rectangles or circles overlaying each other.
Another is hovering line segments and the projecting the nearest hovered point onto the line. That was approximated with SVGs before and was just kind of a bug.
Another example is allowing some “wiggle room” for touching elements without having to render SVGs multiple times with transparent elements and stuff like that.