Interview prep teaches you how to present yourself in a way that is attractive to those conducting the interview and making the decision to hire you.

It will not change who you are. It will not give you experience or skills you do not have. It will show you how to show off the experience and skills you already have in a more flattering light than you otherwise might. The price is very modest for the return on investment. I used Emerald Coast and can recommend them without reservation. I understand Cage is considered the gold standard for United specific prep.

The only wrong choice is to not get professional advice.