I think one thing to call out is that Kenji suggests that seasoning the surface of proteins in advance can have a similar effect on the end product when compared to brining, and he likes this method better because it doesn't dilute flavor, and is also less effort.
I brine fish a lot because the brine is very simple: salt and sugar solution, and the fish is brined quickly. I prefer this especially because the texture of the fish is firmed up ever so slightly.
I also like to brine poultry but do it way less often, but mainly because I want more flavor in the brine: herbs, lemon, etc... and this involves heating, steeping, cooling, and longer hours of brine. So, in my home, I'll mostly season in advance.
Thanks Chris - I'm very interested in learning more the science of brining and how to really make use of the technique with any flexibility in the home kitchen. I refer to some of Thomas Keller's cookbooks often and I'm a fan of his brine for poultry; however, I'm always a little uneasy because I'm not sure how to take some of the variables: time, amount of chicken the brine recipe might expect versus what I have available, etc...
A lot to learn, thanks for the explanation above, and I'll certainly take more pointers and learnings here.