At my firm, we tend to have everyone in the company on each project. This can be a pain when we get a new hire and I have to add them to each project. It would be easier if they were just automatically added when I add them to the company rather than me having to go to each project and add their email one by one. We do this because we often have coworkers who will help on any project if someone is out, and I can't limit the projects to only the people working on them. It wouldn't work at my firm.