I always switch between projects to get some files (Like a CI config I already wrote for another project) or look how I have done something in another code base. Also all my editor configs, bookmarks, browser logins for Github are all there. If I'd have to switch between users for each project that sounds really cumbersome.
When you want to enable some limited sharing, it helps to create a new group for all your user accounts.
For files and directories that you want to share, just set the group to your new user group, and use the OS group permissions to manage read/write/execute.
> Also all my editor configs
My editor and shell configs are in /etc. Again, it may not work for everyone, as you may have to share the computer.
> bookmarks, browser logins for Github are all there. If I'd have to switch between users for each project that sounds really cumbersome.
Sorry, I was unclear. I don't logout/login every time I change project. I have a main user, and use sudo to run commands as other users (it even works with graphical apps, provided you whitelist them)
These are pretty creative approaches using the built-in access control Unix has. I like it.