Traveling to work via public transport, hitting the skies for a holiday, or heading into a meeting in the park with your classmates, you can have access and can collaborate on all of your files with this feature. Offline use for content you have selected allows you to keep working on the go, and wherever you don't have internet access. That is indeed the question! Why use syncing across OneDrive and Teams? Why wouldn't I just save them onto my local drive? Or keep communications and files separate? There are a bunch of different benefits that can make this integration feature super useful.
