- Can be uninstalled easily, and leave no trace behind (remember "Register cleaners"?)
- Cannot interfere with other apps
- Cannot run in the background and spy on your surfing habits
- Cannot steal your credit card information and upload it to Russian mafia servers
For a long time, the standard geek response to these problems is "that's the user's problem -- they should be more careful about what they install". The response appears to be "fuck you, I don't want to waste my time worrying about whether this purple monkey screen saver will secretly empty my retirement account."
If you can find a way to make this "free and open" system also safe, then I think you'll have a winner.