Can someone explain the Scandinavian (center counter) defense

I am a new player (after a few months, up from 700s to 1000 on ELO on chess.com), and I have been encountering this d5 response to my e4. I can't seem to make much sense of why someone would play it. Every time this happens, I take, their Queen takes, and then Nc3. At this point, we are both down a center pawn, but I have open routes for Q and B, an advanced N, and am attacking their Q. It seems to me that I have a large advantage (I have never lost playing as white to this opening except due to time, but then as 1000 player I don't put much weight on my outcomes reflecting true advantages.) Can anyone who plays this defense explain it? What am I missing?