Issue with Ad Campaign

Your add needs to have a minimum number of install

[wolfish]

While trying to run my ad campaign for "App Installation" Vs "App Engagement" I happen to see that Google only allows me to run the campaign for "App Installation" and not App Engagement" ....with a pop-up message " For this campaign to run, your add needs to have a minimum number of installs." Can anyone help me understand why is it so? and what is the minimum, number of installs?

[RhinoFish]

App Engagement Ads = [support.google.com...]

If your app only has 7 users, G is not going to let you run ads within your App, there are too few people because too few have installed your app,

More details:
[support.google.com...]

I don't know the min required, but I do remember that Google recommends your Device List have at least 250k users to perform well.

I believe that Engagement campaigns are for popular apps, not startup apps.

[wolfish]

Thanks, RhinoFish! It was really helpful ... :)