I am no techie so half the current names and TLAs are new to me. I've recently decide to upgrade my old Arcam AVR to new Linn kit which has HDMI inputs. I have some music on iTunes on my MacBook that I've been playing via phono conns but sound is not hi-fi. I've been looking at moving the iTunes library to a 'streamer'. Looked at suggestions of using a Mini Mac, Raspberry pi with associated DAC and other gismos. But then learned that I could upload everything to PLEX and listen via my Roku stick through my new amp. So - here's the question, Why do they still sell music streamers [hardware] and why are people still building their own? What am I missing?