Netflix essentially has Nintendo covered on movies. This way they can offer it as an option and keep the costs associated with licensing disc movie playback out. Nintendo can offer movies, the cost is kept down. Win-win.
Blu-Ray might have been a compelling feature in 2006. 2012? Not so much. Blu-Ray Players are $60. Go get one if you want one, if you somehow wanted one before and don't already have it.
In a 2010 survey, the most common reason cited for buying a PS3 was its Blu Ray capability:
http://kotaku.com/5541239/why-are-people-buying-ps3s
Blu-Ray might have been a compelling feature in 2006. 2012? Not so much. Blu-Ray Players are $60. Go get one if you want one, if you somehow wanted one before and don't already have it.