|The subject of this article was removed from World of Warcraft in patch 4.0.1.
Although 5% may not seem like much, when you take into account the number of times a Warlock casts destruction spells in a normal battle those critical strikes add up quickly. In order to get 5% crit from gear, you need 110.5 crit rating, so this talent can be an easy way to double your crit chance with destruction spells. Many destruction warlocks choose this talent because of that, and the fact they probably already picked up Ruin.
The Devastation/Ruin spec is the subject of ongoing debate in Warlock circles. On the positive side, a mere six talent points provides a significant increase in a Warlocks crit rate, and provides crits that are much more devastating. On the down side, the majority of spells that are cast by a Warlock do not benefit from the Devastation/Ruin talents (before level 70, only one DoT (Immolate) can crit). In addition, the build will require additional sources of +crit to be truly effective, and this is often done at the expense of other stats such and +Stam/Int, +spell dmg., etc. (which benefit the Warlock across nearly all spells and situations).
It should be noted that the 5% crit chance only affects Destruction spells and therefore will not increase the crit chance of critical strike able affliction spells such as Seed of Corruption