> Though it does seem user hostile to remove it, unless the estimate was substantially off and there's no way to fix it.
I think the problem is that users expect percent charge to be a direct, linear correlate of time remaining, but battery discharge isn't linear. Even if it were, predicting time left is tough. Giving the user a percentage rather than a (likely incorrect) time estimate seems like the less bad approach.
> how effective is this data in terms of actually improving their profitability?
I work closely with telemetry data coming back from Windows devices. There's surely a line from collecting this telemetry to an answer to your question, but I've never heard anyone in our group talk about the profitability of this data. In fact, it costs a lot of money to process and store such huge data, which is absolutely a concern -- so there's strong belief (which I share) that this cost of business is worth it because it lets us make what I hope are good decisions about where we should focus our efforts.
The telemetry that comes back encompasses many dimensions of the user experience, and it helps us do things like figure out when an insider feature is ready to GA; what drivers or devices do poorly and how we can improve the experience; how accurately we can predict battery life; etc.
> they can optimize their dark UI patterns to be better at tricking people into setting Edge as their default browser?
I don't think whoever is in charge of 'tricking' people into using Edge actually have the kind of telemetry that most people think about with respect to Windows data collection. A lot of people think there's some sinister plot here -- apparently as evidenced by your phrasing. But if you look at the UI for default programs, it's really just a slightly annoying "are you sure?"-kind of message. (I don't use Edge by default, but I just reset my prefs to Edge then back, and I wasn't harassed again, so this isn't a persistent nagging.)
I think the problem is that users expect percent charge to be a direct, linear correlate of time remaining, but battery discharge isn't linear. Even if it were, predicting time left is tough. Giving the user a percentage rather than a (likely incorrect) time estimate seems like the less bad approach.