In many places certain departments (OB) wears different colors for security reasons. Surgery people often wear the traditional blue scrubs
that are provided by the employer. Psych dress is often casual street clothes.
Some hospitals have certain color coding for different employees - nurses in one, aides in another, etc. Some have no restrictions, and people are free to choose from the myriad of colored and printed scrubs.
As for me, give me good old fashioned whites. They always bleach clean and everyone can spot their nurse.
I have a nagging suspicion that mgt has allowed the proliferation of everyone wearing scrubs to subliminally mislead the patients into thinking there are many more nurses working than there are. Where I work, patients are always asking housekeeping for their pain meds.
In the facilities I have worked, only OB and surgery had scrubs provided. Everyone else buys their own uniforms.