100% agree. I did a sports science degree with the OU and also a PT qualification. Needn’t have done the degree for training clients. I’ve moved on from that career now but a friend who did their PT level 3 did quite well and she wasn’t the most knowledgeable about training clients (that comes with experience) but she WAS great at making little videos for social media etc. and talked herself up a lot. also only took block bookings paid in advance. Very confident for a newbie, and I think it paid off actually.
Besides experience, enthusiasm etc., one of the most important things is self promotion. I’d consider an online digital marketing short course alongside the L3.
Apart from critical thinking and learning to read scientific studies, there’s nothing in the degree that you couldn’t find out on your own. As I recall, there was a lot of sports psychology (Carol Dwek, how athletes cope with retirement from sport, what makes a successful athlete) which is either irrelevant or you could research yourself.
Even the coaching bits don’t go into any further detail than the L3, except that you have to write essays on it and reference papers. The anatomy/physiology and coaching principles as well as sports psychology (fundamentals - in reference to coaching clients)will be covered by your L3. You usually have to complete the L2 Gym Instructor course first. Or you did.
It’s an expensive way to go about it and unless you are fully employed by a gym (not well paid), you will have enough outlay to consider with insurance and equipment etc. you will also need to build up a full schedule to make it worthwhile and also maintain it when people drop out etc, it’s a lot of work and your hours may be unsociable. That said, very rewarding indeed.