Machine learning is one example of a specialty within computer science. Other examples would be: system design, security, web programming, databases, and so on.
Studying a specialty helps you stand out and helps you find jobs. It's pretty rare for a job posting to look only for "general programming"- they're usually looking for people with one or more specialties.
Machine learning is very hot right now and is being used more and more to solve tough problems. I'd say it's definitely worth looking into to see if it interests you, but if it doesn't, don't worry too much because there are plenty of other specialties to explore.