I have a laptop to the side, and a bigger screen in front of me. And the laptop screen might as well be a picture frame: it adds no productivity gain, whatsoever. And it really confuses me. I have fond memories of my setup at work, in the result 2000's, with two big monitors on a desktop machine. I remember it working so well, and I just lost that feeling. Maybe because those were on equal footing, while the laptop screen now is the tiny little brother. Or, I'm just nostalgic and making up benefits that didn't really exist.
I used to use the laptop screen as slack/mail/calendar, and really, rather than helping in any way, it was probably more of a productivity sink: all the interrupts were conveniently more visible.