If you want to display ads in your app, you can display ads promoting your products, or sell ads by yourself, this is what I meant with "do something clever when connected via wifi".
Maybe in the country you live the mobile internet is cheap and unmetered, but the appstore is international, if you don't want to deal with international users, you are free to lock your app by region. It's not your God-given right to use the user's data plan as you wish, even worse, in some countries you are going to waste your user's money in many orders of magnitude to perceive a cent (or less) for a banner.
If you are not going to care about your users, then don't complain about users not caring about your efforts.
Maybe in the country you live the mobile internet is cheap and unmetered, but the appstore is international, if you don't want to deal with international users, you are free to lock your app by region. It's not your God-given right to use the user's data plan as you wish, even worse, in some countries you are going to waste your user's money in many orders of magnitude to perceive a cent (or less) for a banner.
If you are not going to care about your users, then don't complain about users not caring about your efforts.