GM Analysis Question

I am working on a GM Game Analysis for a study and would like some opinions on a move. I'm not sure why it was played, I would appreciate anyone's thoughts on the topic though.

Study: lichess.org/study/MOWE2VsH

Chapter: Symmetrical Variation: GM Game Analysis

Move: Move 17, Qc7 by black.

I am not really sure as well, but I think it could be to line up the Queen with the important h2-b8 diagonal to open up future threats once the pawn on e5 eventually moves.

17...Rb8 looks better. Remind this was a rapid game.