Because having thirty billion integrations and automations, toggles and etc that a new user may mess up is overwhelming for a newcomer. Arduino IDE serves great as a plug-and-play introduction to microcontrollers, allowing people to learn what they're doing before figuring out what the billions of automation tools are and how to tame them. It's the same reason python still has IDLE, it's just notepad with a run button, because it's all you need when you first start getting to grips with everything.