What’s interesting to me is a tool can be terrible at its stated problem and still add value.
I suspect many of the results dieters get is “mere measurement”, e.g. it helps them be more thoughtful, seek education, etc.
So the value of the tool is in its ability to keep them engaged and hopeful (the unstated need), and the actual mechanic doesn’t have to be that good at the stated need.
If I diligently track calories using one of these things and don't lose weight I'll say "screw it" and stop bothering because obviously counting calories doesn't work. I think this is much more likely to be the case because even proper calorie counting is difficult and frustrating
I suspect many of the results dieters get is “mere measurement”, e.g. it helps them be more thoughtful, seek education, etc.
So the value of the tool is in its ability to keep them engaged and hopeful (the unstated need), and the actual mechanic doesn’t have to be that good at the stated need.