The adjustable fire grate does what it does well.

It shifts the "base" of the coals up towards the top where the cooking / heating is done, meaning higher temperatures at the cooking plane.
This also makes briquettes or other fuel sources more efficient as less of the energy is loss over the shorter distance (fewer briquettes required).

I’ve used it on days when unexpected rainstorms damped the wood in the area. Also used it when I wanted a more controlled and uniform cooking fire quickly.

Note, I recommend a second set of sticks because you will need two to support the fire grate. A second set is needed to move the firebox or work other accessories after the grate is set.