Okay watch me completely overinterpret two cards for the fun of it!
I kept looking at the Giovanni SAR card and noticed a few things.
What struck me as odd, was the chess-set. I have no doubt that Giovanni would be skilled, and that he could technically play against himself, but thats not how you set up a board when you play against yourself. When playing chess against yourself ( to try out strategies and movesets ) you place the board in a way where you can reach both sides easily.
Addisionally I noticed the cup of presumably tea or coffee. Its reach is somewhat blocked by the Masterball and therefore just as troublesome to reach as the white figures.
Combine that with Giovannis look out of the window and you get the impression, that his opponent is "there", just not physically in the same room.
Then remember what other card from the same set has a night city in the background.
Reminder that in the anime these two dont know each other just briefly. I also realize that Mewtwos eyes in this art are shining blue, wich indicates it useing its powers. They dont glow when it is just flying.
Now, chances are, that I am just hilariously overinterpreting things. But in my mindset at least, Giovanni and Mewtwo are having a late night little chess session and Mewtwo is making its move from a comfortable, safe distance. And I love that.