In design terms, cooldown can also be thought of as an inverted 'casting time' where instead of requiring a wait time before using an ability, cooldown may replace casting time and put the wait after the ability is activated. This creates a new dimension to the balancing act of casting speed versus power: "lower cooldown, faster cast, but weaker strength" versus "higher cooldown, slower cast, but greater strength." This sort of mechanic is integral to such games as World of Warcraft, where cooldown management is key to higher-level play and various abilities deal with cooldown (for example, cooldown reduction or immediately finishing cooldown on certain abilities).
From the technical point of view, cooldown can also be used to assert control over frequency of cast (for spamming) in order to maintain a fluid frame rate and ping. For example, in the game Diablo II, cooldown was added in the form of a patch to several graphically and CPU intensive spells (blizzard, frozen orb, hydra, etc.) to solve the problem of extreme lag caused by players spamming these spells in multiplayer.
Spells, skills and weapons in DeathSpank will have a cooldown. This will prevent them form being over used and will normally mean they are stronger than normal attacks.