I understand that you are wondering which method to use to store your course content.
Commons is a super helpful tool if you just need to backup your course, share content with others, and allow other teachers at your institution to copy your content. Updates to content can be pushed to courses that have had the content previously imported if needed. Many instructors will use Commons if they just want to back up their course content, or allow other instructors to copy the content into their course. HERE is the Commons guides if you want to look at details on it.
You can use Google drive also. There is not a real disadvantage that I can think of with using Drive instead, other than it will take up some of your storage space on Google Drive.
Hopefully this helps!