I was going to post this as a question - but while making this forum post I figured it out.
As I don’t seem to find this answer anywhere else on the forum, I thought it’s a good idea to have it here written down.
IF you want to make public the number of users your app has on the front page, privacy settings will stop this.
So to solve this I had to go to Database - > Privacy → Users → “Everyone else (default permissions)” and check the “Find this in searches” checkbox.
Info about these users is not public (name, e-mail, etc.) but their :count is now public and visible.
Hope this helps someone someday.