You seem to be looking at the choice of opt-in vs. opt-out from the perspective of a user who actually cares about the feature.
Much more common, though, I'd say, is the type of user who will accept whatever the default is, because they just don't care.
Compare: the organ-donor registry. When it's opt-in, most people don't opt in. When it's opt-out, most people don't opt out. Most people just don't care.
If you think something is good for people, you have to consider the large group of users who don't want to put in the time/energy to evaluate whether the thing is good for them, but just want the program to shut up and do what it does by default—whatever that is.
Much more common, though, I'd say, is the type of user who will accept whatever the default is, because they just don't care.
Compare: the organ-donor registry. When it's opt-in, most people don't opt in. When it's opt-out, most people don't opt out. Most people just don't care.
If you think something is good for people, you have to consider the large group of users who don't want to put in the time/energy to evaluate whether the thing is good for them, but just want the program to shut up and do what it does by default—whatever that is.