You can staple it down - not as messy and fairly quick. I've used something like this on a remodel. It was 3/8" cork over plywood subfloor, then bamboo on top.
I wouldn't staple cork. Cork is brittle. Cork expands a bit, especially if it gets a little damp. If it expands and contracts enough the staples will tear and then you will have nothing keeping it together 4 years later. Probably why manufacturer says to glue. Taping the seams with something that handles moisture well is the best solution.
Could someone explain this recommendation "around the perimeter you are taping your cork to the subfloor directly along the outside edge"?
Here is how I understood it. Let's assume we work with 2'x3' cork mats. Lets start from a corner. One places duck tape sticky side down for 3' on the subfloor, along the perimeter of one wall starting from the corner, then folds the tape back onto itself to expose sticky face for cork piece #1. Since are in a corner one places another fold back tape for 2 feet along the other perpendicular wall.
Cork piece #1 in the middle of long side parallel to short sides has a folding back duck tape to expose sticky side to subfloor. Then #1 get attached to subfloor along its middle andd along its outside edges parallel to walls, 1/4 inch spaced from walls to allow expansion? We could prep #2 so it has a middle sticky side do tape exposed. It will bump against the wall on its outside short edge. so a fold-back tape along wall could be prepped? Now we lay #2 next to #1 along their long side. Attach its bottom short edge 1/4 in from wall. Now along their long edges they are touching place a tape to join them. Did I get it?