People who install a tooth brushing app will probably buy all kinds of electronics stuff, so I'd wager that such a list would be somewhat valuable.

Honestly, even if it's not sustainable and never ends up profitable, I'd be willing to bet there are multiple entities that exist that would pay you some ridiculous amount of money for that info just to try to resell that info or attempt to monetize it directly "some day".

Think about how many companies have pivoted to burning cash on adding "AI" to their products. How many of those cases are going to end up actually being a good business decision? Probably very few. It's likely the same with everyone just wanting "data" to "analyze"--even if they have no idea how it might be useful.