Why do I need an additional player device if I have a Roon nucleus and a dac?

Your Roon Nucleus can serve the function of feeding directly to the Chord as long as it’s placed close enough to connect with a quality USB cable. You would need an additional player (render) only if you want to place the Nucleus away from your equipment and have the music from the nucleus traveling on you network. The Chord TT2 does not have an Ethernet input so another unit would be required to receive the Ethernet or WiFi signal and convert it to USB for input to the Chord.  You may need something like an iPad for control of the nucleus no matter where it is placed.  

If you wish to place a Nucleus in another room you can use a raspberry pi4 running Ropiee to connect to the DAC. It acts as a bridge. 

Thanks all and especially drrsutliff.  Streaming equipment can be abit challenging to understand, and it don’t need to be.  So easy to make a purchase mistake, etc. 

Two scenarios where you would need a separate streamer

1 is if you wanted to use a service that wasn't supported by your Nucleus (Spotify, Amazon, Pandora) and did not want to connect a PC to your DAC.  As long as you are using your library and Tidal or Qobuz you are good. 

2. The one other scenario (and I face this) is if you can get an ethernet connection close to your system.  My ethernet is 20' away and in a closet and adding a hot spot has proven challenging.  Unfortunately the streamer I chose is not a proper Roon endpoint at the moment (Chord 2Go) and I am stuck connecting to it via airplay.  I am irritated with Chord at the moment (and Roon).  There was no need to implement this certified endpoint restriction in the middle of COVID 19.  

Thanks verdantaudio,
great info.

i will likely get the nucleus.
my Ethernet occurs by splitting the incoming tv cable, supports modem and tv.  A hole in floor is how cable comes into room. Also, via router I feed Ethernet to this room and a downstairs room via hole in floor.