I wonder why an emergency team would need to know if you have copd?

For care... For proper care to be given, the emergency team needs to know as much about you as possible, including any diseases you have, prior surgeries, current med list, etc. If you have copd, you may have chronic lung issues and certain therapies may be dangerous for you and would likely not be given if your COPD was known.
Alters treatment . Knowing a patients medical condition is vital to determining what is wrong and what to do about it. For example, a patient with COPD who is having an exacerbation (short of breath, fatigued, confused) and has a normal chest x-ray but is having hyperpercarbic respiratory failure, the patient should be tried on bipap rather than getting a breathing tube.
Copd. Emt should know whatever available medical history to treat you appropriately. For example if they know that you have COPD they will not administer too much oxygen which may be detrimental to your health.