Hey,

Subtasks are a great idea, especially that you can convert it into project with tasks.

However you can't see if you have any subtasks if you see a list of tasks. You must enter a task to see that it has some subtasks. Moreover if you mark the task as done, you sometimes forget that there were subtasks.

It would be better to mark it with some icon or something to show that the task has also subtasks.

Best Regards,
Paweł Kryla