Fissure is used primarily for initiating stuns on the enemy. The stun can help set the opportunity for other spells that are difficult to land on moving targets. Fissure is an effective means of trapping/protection, creating a wall to protect your allies and cut off enemy escapes. Other techniques involve timing your fissure to counter enemy stuns and control the team fight better, stunning the enemy to prevent them from repositioning or casting spells. This makes enemy damage output as inefficient as possible and disrupts their spell combos.