I guess it's really safe cause it's open source, you can make notes on your habits but don't really do that. Its simple. Really fast. Haven't found a way to connect it to notion. In general it's a great app to track you habits. Does its job. Not more, not less.
Habitica - Habitica is a free habit building and productivity application.
Journalistic - A simple, yet powerful micro journaling app
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Nomie - Open-source mood and life tracking
HabitBull - HabitBull
Day One - A simple journal application for the Mac, iPhone, and iPad. AboutTo learn more about Day One, see these two excellent reviews . PublishPublish is not available in Day One 2.