The problem with the tool is that while it may work fine for simple shapes (like dice), it will make a mess out a more complex one. Try doing something concave / irregular and watch it squirm, producing chaos… It’s sometimes better to add shapes manually, tbh.
What you’re suggesting is an OK quick fix or for a somewhat regular shape. But if you want a neat and efficient simple collision, you will need UCX as mentioned above.
Not sure why Ben_Cykyria had performance issues with it. You absolutely must simplify the shape before exporting - perhaps the attempt was per poly.
Old tut that is still very valid today:
