as far as i know, this is what is written on their policy page
"Google ads may not be placed on pages that promise payment or incentives to users who click on ads, surf the web, read emails, or perform other similar tasks. Placing Google ads on such pages may result in invalid impressions or clicks and is therefore prohibited. Similarly, Google ads may not be placed on pages that primarily drive traffic to, promote, or provide instructional materials on how to implement such services."
Just wanted to confirm, because your app looks interesting.
A regular license allows an item to be used in one project for either personal or commercial use by you or on behalf of a client. The item cannot be offered for resale either on its own or as part of a project. Distribution of source files is not permitted.
An extended license allows an item to be used in unlimited projects for either personal or commercial use. The item cannot be offered for resale "as-is". It is allowed to distribute/sublicense the source files as part of a larger project.