inhale steroids, should I carry medical ID?

I'm a 57 year old female who has had asthma for about 6 years. Recently my asthma has taken a new pattern,in that symptoms are more frequent thus prompting my allergist to prescribe Symbicort, to be used on an on going basis.
In the information supplied by the pharmacist, and on the leaflet that came in the box with the inhaler, it was consistently emphasized that people who used inhaled steroids on a long term basis, should carry medical ID.
Why is that? As well,there seems to be a concern re Symbicort, and low potassium. I take hydrochlorothiazide, and have had low potassium. Fatigue is one symptom, but other conditions cause fatigue. Are there test strips to detect low potassium?