I'd be motivated by the swear jar & reminders since I (would have) put it there intentionally. But I realize not everyone lives this way and busy life can be distracting.

You're very right it would depend much on the person AND the goal.

The main value I personally see here is the setup. I wouldn't have to set up reminders and tracking manually. I may even learn a new goal I hadn't considered if others share their goals. As long as it doesn't devolve into a perfectionism race to the burnout line.

I hope it results into more a tool for self improvement than yet another business preying on human flaws/needs.