When creating a new project, you can select a group whose users will have access to the project. However, this only works once, it would be nicer if the group could be optionally bound to the project:

In the current state, the groups don't make that much sense to me. I only need a group when initially creating a project. That means I create the group and assign the users, then create the project and add the group users. Afterwards I can delete the group since it only has an effect when creating a project.

I am sure that also the current status has a use case for some users. So optionally binding the group to the project would be a good enhancement.