How will you design controller vibration signals with different game events during VR games?

Hi all, I am a student researcher in HCI (Human Computer Interaction) field.
During my recent research on VR commercial games, I noticed that developers incorporated two distinct modes for controller vibrations in the game. For instance, when attacked by zombies, both controllers vibrate simultaneously, while when firing a gun, only one controller vibrates. I am curious to learn about the specific design principles that guided these decisions and also hear about your experiences in game development.
I would greatly appreciate it if you could share any insights into the design considerations that led to these different vibration modes. Additionally, I am interested in hearing about your experiences and expertise in the field of game development.