The definition is a little higher. If you have a wide screen huge television than you can see a difference. On the other hand if you have a 19" TV it's probably not worth the expense. Although, many of the BlueRay players also come with internet content so you can order movies on your TV. That can be nice.
Its hard to say if they are taking jobs away. Personally I think Netflix and the like are doing more damage though I admit I enjoy the service. Where I live, most of the movie rental stores have gone out of business. I suspect it is more because between the economy making people watch their spending and netflix letting you order a movie form home, the desire to drive to town and rent a movie is less than it used to be.