I'm testing a dry-month app for couples before I build it. Would you use this?

I'm building a small iPhone app called Clinkless for people who want to take a month off alcohol together, with a partner or a few friends. How it would work: - You start a 31-day month and invite someone with a link (no accounts). - Each evening you both tap "still dry" or log a drink. A slip doesn't reset everything. - You see each other's streak and get a nudge when the other person checks in. - At the end you get a "body report" from Apple Health: sleep, resting heart rate, plus money and calories saved, as a card you can keep or share. - Data stays on the phone. Free to start, one-time unlock, no subscription. Stage: there is no app yet, only a landing page with a beta list. I'm a non-developer building this with AI help, and I decide in mid-November, based on signups, whether it's worth building in time for January. Three things I'd love honest answers to: Would you do a dry month with someone else, or do you prefer doing it alone? Is the sleep/heart rate report a real reason to try it, or a gimmick? What would stop you from downloading it? Landing page with screenshots of the planned design: clinkless.alanisko.workers.dev Thanks, I'll reply to every comment.