What is One Drive migration and why we should do it?

OneDrive is the Microsoft cloud service that connects you to all your files. It lets you store and protect your files, share them with others, and get to them from anywhere on all your devices. When you use OneDrive with an account provided by your company or school, it's sometimes called "OneDrive for work or school." It used to be known as "OneDrive for Business," so you may still see it called that in places. One of the wins for Office 365 customers who have OneDrive for Business included in their licensing is to migrate users’ personal files to OneDrive.
For files that are stored in home drives on traditional file servers, the reduction in server and storage costs is a benefit. For other personal files stored on local computers, moving the files to OneDrive so that they are safely stored in the cloud is also a benefit.

Generally speaking, OneDrive for business migration also works well.

“My documents” scenarios
Simple sharing of documents between small groups of collaborators
Storing data in the cloud where compliance and security can be enforced
Syncing files to mobile computers and devices for working offline or remotely
The OneDrive sync client can also synchronize files from SharePoint libraries for offline access to team files. So having it configure and ready to go is useful to end users who travel or work in places with poor connectivity.

I hope this information will be useful!
Paul Wilson