Uploading and downloading files from Google Drive is a great way to transfer files between devices and share them with others.

For instance, if you have a PDF file, you can open it in Adobe Acrobat or another PDF reader directly from Google Drive. This integration saves you from manually downloading and re-uploading files ...

This is especially true of PDF files since Chrome can't open them natively and thus hands them over to other applications, the default being Google Drive's PDF viewer.