Nature of the beast. It is first & foremost a V-Carve path, which will v-carve everything you have selected.
The secondary feature is the Inlay mode, which allows it to calculate the offsets required to make the male plug fit the female pocket.
You are correct, in most cases with inlay mode you don’t need to V cut the outer boundary.
Although in most cases it’s not wasting a LOT of time, just a bit.