Well, in both cases, dtube and steemit, its just a link. If something is on the ipfs network which you dont need steem(it) or dtube for, you can at least link to it like so, you dont need dtube for that - and i think embedding a video directly into the post should also be possible though ive not dealt extensivly with html in order to know how exactly you embed a video file. Personaly i tended to watch sempers videos through the direct link (labled IPFS in the article) anyways and dtube is unneccessary for that.