The value of getting your CFI II or MEI is not the ability to make money. You simply won't make enough to fool yourself into think there is any real monetary value to it. You will spend countless hours waiting on students that don't show and more than half of the students that do show will bring dangerous attitudes with them that will make you question why you're taking the risk for $300 a week.
The only real reason anyone should be looking at getting their CFI is because they have a desire to teach. Beyond that you need to ensure that your strive to improve your quality as an instructor and educator.
I don't fly full time and I don't really like my full time job. It is a job and it pays me very well for the hours I am required to put in. I am also home every night to sleep in my own bed. Believe it or not wife is even happy to see me most of the time.
For fun I teach part time at two seperate flight schools. Now pay attention to that last sentence. I do it for fun and there really isn't any other reason. I get paid less and have to travel further than my day job but I love it. If you don't love teaching don't try being a CFI. I am saying this not only for your sake but that of your future students.
Good luck with whatever decisions you make.