Not using the powers was probably the right decision, honestly. He doesn't really know how to use them and it could have gone south in a number of ways. There was paparazzi there because of Lady Steel. I imagine there might be fallout if word got out that some Dude splattered three guys in a bar with Moonsong or Emerald's power while hanging out with Lady Steel. He opted to stall until Lady Steel was done in the bathroom but he didn't account for the fact that she was an evening shitter.
It's a recurring thing that several characters are blabbermouths. I actually think it's a running gag at this point, particularly with Moonsong's sexual proclivities. She told him not to tell anyone, but that apparently excludes literally everyone they interact with
. Even Moonsong has told several people at this point, so I guess it's not much of a secret.
As for the convo with Anna, he tells her that his power is that any woman he has sex with falls asleep for hours but they get a mindblowing orgasm from it first. It was apparently a plausible cover because they bought it immediately.