Shared Drives are owned by a team whereas My Drive is owned by an individual.
So the difference between Shared Drives and My Drive is exactly what it sounds like.
This means with Shared Drives you can have people join your team, or even leave your team, the files stay put and can continued to be accessed - it's not going to affect where the files are stored so your team can still get work done.
Consider using a shared drive in these situations:
You’re working on a project or event with a group of people who all need access to the same files.
Most of your files are shared with the same group of people.
Your files share a consistent theme or topic.
The content you want to store isn’t personal and is of interest to a specific team or group
Common uses for shared drives include:
Projects—For people involved in the same project.
Events—For people working for a defined period of time on a specific event or deliverable.
Templates—For files that people can copy and reuse.
Company-wide files—For files everyone needs access to, such as training files.
Sensitive files—For highly sensitive files, where you can add extra security to limit access.