Projects are a great way to logically group together containers and I have started using them as soon as I discovered they exist, a few months ago.
I would like to propose some improvements and collect feedback from other users:
Allow working on a different projects in different terminals, that is define the scope of the project selection. I may need to work on two different projects at the same time, but as for now I need to do a switch operation if I want to issue a command on the other project.
Allow starting and moving containers in other projects without being on that project scope, for example by putting the project name before the container:
lxc start project-name/container-name
lxc move project-name/container-name project-name-target/container-name
Allow listing all the projects along all the instances. There is already some work on this, details here
Give clear indication to the user of the currently selected project. A good example is Python virtualenv, that puts the environment name in the shell prompt.
It would be great to have some feedback on whether these requests make sense and if there is some effort in developing them.