Just a bit of pondering on my part!
If I understand it correctly, streaming means that a piece of media is sent out and read in real time (although there may be buffering), byte by byte. Whereas accessing a media file by a network share/SMB isn't actually streaming as the the player gets hold of a file and reads it directly. Is this right?
So is DLNA exclusively a streaming protocol? What does MC do when a DLNA Player/Renderer requests a file? Does it read the file and then spit it out again byte by byte so that the player never actually sees the file itself but just a stream of bytes?
With SMB, there is no piece of server software in between that does this, the file is accessed directly, so it's not streaming.
In other words, media players that can only access files via SMB or via attached USB storage can not really be called streamers, yet that's what they're generally referred to as.