Yuzu's flashback was definitely interesting. Minami views her as just a shy but kind girl, but the flashback shows she was (is?) actually straight-up antisocial and had to be relentlessly badgered to open up to her. It shows that Minami perhaps does not understand her best friend as much as she thinks she does.
I normally really hate the interrupted confession trope, but Minami has been proactive enough that I'm hopeful this won't actually be a setback. As b58 says the current dynamic will get old fast, and I think a real confession from Minami at the end of the volume would open up a lot of more interesting story possibilities.