Personal training and group exercise instruction are very different.
In group, you have to be concerned with the safety of many people, so the moves you teach are limited by contraindications. You have to be able to manage a crowd, are constantly scanning every member, and you’re providing multiple levels of options for people, simultaneously.
In personal training, you have to focus on one person, what their goals are, what their injury history is, and act in a way that’s specifically designed to help them.
Personal training isn’t in the scope of a group exercise certification.
More later. I have to go teach group-ex. 🙂