No, Felipe. You could change it slightly, however, and say "It is no longer worthwhile", "It is no longer worth our while/time", etc.
An alternative is "If your child does not think this course is paying off..."
TO PAY OFF (to be beneficial, worthwhile, a good investment)
If you study hard, it will pay off in time.
Hard work pays off.
If I move to the capital, I am sure I can find a good job. The move will pay off.
Instead of getting a job, I studied for another year and got a master's degree. Eventually it paid off.