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.
Classpass - Workout at the best studios in your city.
Habitica - Habitica is a free habit building and productivity application.
Gympass - Gympass is a fitness discovery platform connecting the world's network of fitness facilities to companies and its employees.
HabitBull - HabitBull
TrainAway - Find and access gyms near you.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.