Try to clear a sea can village and walk up and down stairways, and you will find the ingenuity of mounting a red dot high over the primary optic. It allows you to keep you head up and retain more situation awareness. In addition, you can use the reddot if you are wearing head gear, like CBRN mask. It is a different tool from the 1X setting of the Spectre DR.
clearing a sea can village? hummm i'd like to know more, sounds hairy.