Written in 2019 by Kaoru
It has always been beneficial to use elemental weaknesses against your enemies, especially in the many Megami Tensei games. But the system really came into its own with 2003's Shin Megami Tensei III: Nocturne on the PS2. This game introduced the "Press Turn System". This meant that you generally get as many actions a turn as you have fighters in your team at the outset. But if you would hit an enemy's weakness only half a turn would be consumed, resulting in being able to get up to double the amount of actions if you played your cards right. On the other hand, if an attack misses or is nullified, two actions are eaten up. This doesn't just apply to the player but also the enemies. Thus it is crucial to change your team setup in a way that makes it easy to exploit the opponents weaknesses while covering for their more sinister attacks.
This was so genious that almost all games in the franchise have used this system to a degree since. The Shin Megami Tensei IV and Digital Devil Saga games use the "Press Turn System" exactly the same way. Meanwhile in Persona 3-5 hitting a weakness knocks down an enemy on top of giving you an extra action, and if all are knocked down at the same time, you can unleash a powerful group attack on them. And Shin Megami Tensei: Strange Journey has the demons in your team sometimes do a follow-up attack free of charge if you hit the enemy's weak point.