This ability can be considered the equivalent of the rogue ability [Cheap Shot]. Unlike Cheap Shot, Pounce has an additional bleed effect, and Pounce costs 50 energy compared to the 40 energy cost of Cheap Shot. Also, Pounce awards only one combo point while Cheap Shot awards two.
A helpful initial attack when you need to get in a couple of attacks before the target has a chance to do anything.
Also helpful when sneak attacking an enemy with a group.
However, if you wish to deal the most damage possible in a shorter duration and/or if stun or bleeding effects aren't useful on your target (immunity, for example), you may use [Ravage] as an opener. Some things that are immune to bleeds can still be affected by the stun, which may allow you to get off one or more Shreds.
Patch 6.0.2 (2014-10-14): Removed, but its effects has been incorporated into [Rake].