It turns out that TikTok added privacy controls that can allow advertisers to use your videos in their ads. Also, you can see your ad interests predicted by TikTok platform. These new options can be found in the Settings - Privacy section.
In order to allow your videos to be used by advertisers:
- Open profile page
- Oper settings page via 3 dots menu
- Open Privacy section
- Enable "Ad authorisation setting"
This setting will allow Advertisers to use your videos in their ads so the video can get more views.