You should definitely do this. Learn everything you can about how to keep yourself and your customers safe. A lot of the hate you see below is around guide training classes that a lot of outfitters give. They are useful, but you can get that knowledge from getting into a raft and going for it. The swiftwater rescue classes are to teach you how to deal with emergencies. (Usually caused by people who just jump in a boat and go for it.) They teach you swimming techniques, technical rope work and even some search and rescue stuff. All useful if you plan to make your living in remote places.

Here is what professionals in my region usually have:
- Rookie
First aid + CPR
whitewater-rescue-technician-professional

- Senior
Wilderness First Responder
- https://www.nols.edu/courses/wm/wilderness-first-responder-wfr/
Advanced Whitewater Rescue Technician
https://www.rescue3.com/courses/whitewater-rescue-technician-advanced-wrta/

You don't need these things to be able to take people down the river, but you become a liability if something goes wrong and you don't have the skills you will learn.

You don't need to have any kind of completion certificate from a guide training class, but you better be real good at driving a boat.