Actually, WP doesn't lower the cool down, it lowers the amount of time added to the cool down when being attacked. At 200 WP (1 sorrowblade + 1 heavy steel), This time is reduced to 0, meaning you can go into stealth mid-combat. This allows you to reload your glimmershot while your opponent can't see you. On the other hand, building 250 CP (1 shatterglass + 1 frostburn) allows you to stay invisible long enough to use your ability a second time, so you can stay invisible for a long time until...