MOOC's can definitely set you apart in job interviews and but does not guarantee you a job. This is because a certificate does not gain the employers trust and hence is not as important to them as your skills. If you genuinely want to learn something, apply the concepts you learned by yourself and move on to discover more about the subject, that’s when an online course really ends up helping you. You can also flaunt some project you did based on the course which might impress them.
So, remember to take your time and learn the concepts well rather than rushing just to complete the course and adding it to your CV.