All organizations using Office 365 Groups will benefit from the full SharePoint Team Site experience as it has become generally available and rolls out to all Office 365 tenants this month. This means that group members can create more document libraries, image libraries, lists, or start to use the modern team site experience. One thing the IT Pro and the Power User takes for granted is that the typical user has always struggled to find their team site and save their documents in a place where their team can collaborate on them. They take the path of least resistance and save it to their desktop, then email the changes to their group. OneDrive and file syncing helps in a small way to make it easier, and if the typical user can come to understand how to share files using guest links or sending an invite, they may do that occasionally. But it is better to save the document directly to a space that your group can collaborate on that document, where there is version control or where you can co-author. Office 365 Groups and their team sites go a long way to make this experience easier. Take the example of receiving an email with an attachment. I may receive an email directly from a client and it relates to a project. Other group members will be interested in the document and may need to work on it. I forward the email to the Office 365 Group for the project. All the people who are working on the project are members of the Group. They can read the conversation and respond to it. The document can be saved directly to the shared documents for the Group and in just a couple of clicks, it is in a truly collaborative place and no longer needs to be emailed around. Now that the full team site is available to an Office 365 Group, additional libraries can be created. The document can be moved to a different library for a different purpose. The group members can also easily find the team site related to their project. Other content, apps, lists, news articles can all be added to the site, making the collaborative experience for the project much richer.
This video illustrates just one of the benefits of having a full team site for an Office 365 Group. I think it's one of the most important benefits because it empowers the typical user to more easily use SharePoint.