Employment means you are employed. If you start a company, you are an employee of said company ("self-employed" is a misnomer if you have a corporation). "A project," implies that there is not a company, otherwise you would say that you started a company. "A project," does not constitute employment.
You can talk about edge cases of pet projects making sales, but it doesn't change the fact that claiming a project as employment experience is unlikely to get you very far.
Again, I am not saying that people should not work on projects. Just don't confuse projects with employment.