People buy hardware to use their advertised features. If you are the type of person that only needs 2D rendering and video then you should use an Intel GPU. I would assume people who buy a state-of-the-art dedicated GPU want to use them for actual 3D acceleration.
Or possibly the advertised feature they're interested in is 'ridiculous number of attached monitors'. Intel GPUs generally only have a couple of display connectors; if you want a card with a lot of physical ports you'll want to buy a discrete GPU whether or not it support 3D acceleration.
People buy hardware to use their advertised features. If you are the type of person that only needs 2D rendering and video then you should use an Intel GPU. I would assume people who buy a state-of-the-art dedicated GPU want to use them for actual 3D acceleration.