It's not just L-brackets, but a great many adaptors, rings, camera bayonets, extensions, plates, etc. And the same is true for tripods and tripod heads, focus rails, view cameras, and on and on. The camera brand can only go so far. We have to morph it the rest of the way depending on where we are headed. Nikon does not know all of what I use or need.
If you don't use tripods, heads, adaptors, L-Brackets, and so on, of course you don't need them. I need them, especially if I am going to try and take a hundred or so images without anything moving and then combine them into a single image. And I am not even going to mention software, which also is crucial or computer storage.
IMO, we each are on our photo path and journey. Only we can determine what we need to bring with us. You are free to go "naked" of any encumbrance. I am also free to accompany my camera with whatever makes the job easier or possible.