All in all, this is a great app for basic habit tracking & management. There's definitely a few kinks to work out though & I really wish that Google had a more robust system for tasks.
This feature of Google Calendar (an app I use everyday) is a mistaken attempt to solve a real problem. Users want to be able to put more tasks in their calendar but the current problem is one of basic task optimization, not learning over time. In other words, the challenge is how to manage a lot of tasks via their attributes, which this feature does a poor job doing. Instead, it takes a simplified version of what a task is so that it can compare them over time. Instead, tasks are already complex from their moment of inception, so making them simplified so a program can "understand" them is a step in the wrong direction.
What users want to do is retain the complexity, and get help in optimizing their placement in their calendar. This includes even the way the task is expressed in writing.
Perhaps one day, machine learning may help, but it will only come long after the more basic question of optimization has been answered by the right combination of calendar app and human habits.