This is an issue of transparency. If you plan to do anything else with that data beyond how many users use it then who is going to communicate that to the user?

This is an issue of transparency. If you plan to do anything else with that data beyond how many users use it then who is going to communicate that to the user? Is it ok to just keep quiet about it? This is what the issue is here, people are not being told in clear terms what the data is being used for, and that where things become decidedly shady. It's about using the catchall 'improve user experience' to lull users into complacency to conceal what 'else' you are doing with the data. And I suspect that's not what you are trying to defend.