For some things, home study is an option. Having some practical experience can be very helpful. In the instance of becoming a fitnesss instructor, actually taking fitness classes or some personal training sessions would be very helpful. You may even be able to connect with a fitness instructor and set up a mentoring situation.
For many courses, home study is the only option. The courses do not have a live presentation option.
I teach certification prep courses and CECs only as a live presentation. Some people come to the Big Island of Hawaii (where I am based) for my classes as a Continuing Education vacation. Sometimes groups bring me to their facility. Check out my website if you are interested, www.hawaiifitnessacademy.com .