Ask HN: Does anyone use Google Tasks?

Google Tasks (which has been attached to the desktop version of Gmail for some time) doesn't have a client for Android or iOS (from Google).

Does anyone know why? Why were separate "reminders" added to Google Calendar?

Does anyone use Tasks? I find it to be a great, simple hierarchical task manager, which alone makes it more functional for the way I think than almost any other task manager.

(Why do so few task managers support hierarchies, especially in a natural outline-like manner?)