Hi Tre!
I'm lazy, so if I shorten words, I'm sorry.
The main reason, I think, that there is the .cfg file, and the conf.d folder is so that you can swap formations in and out more easily.
I leave the AICarriers.cfg file alone. If I want to add formations, or hoist loads, etc, I just drop a .cfg file into the conf.d folder. All done, or want something different, remove the one you were using, drop in the new one. I personally make a BACK folder under the conf.d folder, and keep all my .cfg files there. I only have what seems like a few hundred
If I want to use one, drop a copy into the conf.d folder. New one in, delete the old. Saves a ton of time.
Remember the fewer formations, boats, hoist loads, etc you have to sort through in the SHFT+J menu, the quicker and easier it is to find what you want. I would rather have 2 menu pages than 10 to search through. And, as I mentioned, I'm lazy. If you keep adding things to the AICarriers.cfg file, you wind up with a long, unwieldy SHFT+J menu.
It is also more dangerous. What happens if you corrupt the AICarriers.cfg file somehow? It can mess up the entire program, or stop it from opening entirely. Safer to drop .cfg files into the conf.d folder, and delete them when adding something else. Just make sure you keep an original stashed away someplace so you can re-use it any time you like.
Long-winded, I know, but that's me
Pat☺