If you get used to posting your cool pictures to something like Instagram or Flickr, you can a lot about your pictures and your picture-based presence on social media.

Opensource app devs have gone wild before and there is a chance of repo hacking by a third party. 

You can't revert deletions. 

Yes, it's way less trust. But there is still a lot of trust. Especially for users that are just running the apps with default relay sets that can disappear at any moment.