Yes, it's the equivalent of Bitcoin Core for the Liquid world, but I don't think the second part is true for either Core or Elements ("only useful to...").
I would assume it has an integrated wallet, just like Core, but I really haven't dug around much. Still waiting for IBD to finish. 50% of the way there.
My main use case was to find a better way to do a Liquid cold wallet with Jade or Specter DIY. Green doesn't give me what I want.
But Specter Desktop dropped their Liquid integration, so now I'm not sure what options are even out there.