It isn’t easy to get a degree from an accredited college/university. Not that getting a certification is easy, but it takes less time and study than 4 years +.
If you have a college degree in exercise science, why not get the certification as the cherry on top.
If you only have a NCCA accredited certification, why not get all the education you can to place on top. You may not go to college, but you can get a lot of additional education after your certification.