Will going through the course help me be employable as a data scientist?

Yes, but you'll have to do work on your own alongside Dataquest.  

We've had quite a few people get jobs after going through Dataquest — you can read more about their stories, here.

The way they did it was to go through the Dataquest curriculum, work on our projects, and then work on their own projects simultaneously.  This helps you build a portfolio, and develop the right skills to perform "real-world" data science.  Here's a blog post that will give you a good idea of our philosophy on learning data science:  How to learn data science