The object of the video was to have one tool in your hand to do a tool change in the Mill. Adding a hammer to the Spindle Nut Wrench was to be able to loosen the Spindle Nut with the wrench, then tap the top of the Spindle Nut with the lead hammer to loosen the collet. Then remove whatever tool is in the Mill. You already have a hand over your head. putting down the wrench and picking up a hammer, wastes time!
Tubalcain makes a combination 3/4″ wrench & lead hammer to tighten & loosen the draw bar on a Bridgeport mill. This is version 2 (made with lead) . Be sure & watch Tips #143 which is version 1 made with brass.