Here's why it's the perfect place:
* Secrecy: The Room of Requirement is hidden and can't be easily found by those who don't need it, making it a safe and secure place to practice.
* Adaptability: The room changes based on its user's needs. It can provide space for training, storing equipment, and even practicing spells that require specific environments.
* Accessibility: The Room of Requirement is accessible to anyone who needs it, allowing Dumbledore's Army members to meet without worrying about being caught.
Although the specific location within Hogwarts changes, the Room of Requirement is always the chosen spot for their practices.