Sort of ...
What it seems to do is add an adjustment brush that matches the settings of the gradient, or reverses the adjustment of the gradient. But it is not actually part of the gradient, and once you create it you can’t edit it independently ... there is only one brush and if you make a mistake, you’re best recourse is to clear the brush and start over. . If you readjust the gradient, the brush changes are unaffected ... I guess that’s the most logical approach anyway.
Overall seems very useful ... but there will still be times when using a regular adjustment brush with matching or offsetting values will allow more control.