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.