I used a time stamp to skip right to the section that covered what I'm talking about here. But did you see the bit before that about the Namco arcade cabinet that allowed PS1 & Dreamcast to arcade cross saving? Here's a photo of that cabinet that had ports for S1 and Dreamcast memory cards:
Yeah, that was interesting as well! I vaguely remember seeing an arcade cabinet somewhere in my city that had memory card slots. I can't remember which game it was though. Maybe it was MvC2 one like in your photo.