Yes, it conveys sarcasm as you say, but the degree of sarcasm it conveys can vary by context and tone of voice; it can range from a rather gentle gibe to great disdain. It can be like calling the other person "a bullshitter" or a "poser" or even a "dirty liar".
Let's say you were having a dispute with a business partner who wanted to do something his way, Option A, and you wanted to do something your way, Option B, and you reach a compromise approach, Plan C. But then without consulting you, your partner goes ahead with Option A. If you wanted to express the idea that you think your business partner never had any intention of compromising, and that you think the less of him for it, you could say:
Like you were ever going to choose Option C!
That could be rather like saying I don't want to hear any more of your B.S. That's it! We are through as business partners.
So you need to take care when using it that you don't give the wrong impression.