Why some Model doesn't implement Init() method?

[RadhiFadlillah]

From what I understand, every custom model for BubbleTea must implement tea.Model interface for composability. However, from 15 models in this Bubbles package only 5 of them that implement Init() method. I thought the least we must do is creating an empty init function like how Progress.Model do:

// Init exists to satisfy the tea.Model interface.
func (m Model) Init() tea.Cmd {
	return nil
}

Personally I prefer if every model implements Init() method, at least for consistency. Are there any reasons on why some models don't implement it?

Thanks!