I must admit that there are two pieces of stovepipe wire remaining in one of my kayaks. They twisted off and got left behind. And, when I fasten pad eyes to the side of the boats so I can attach inflatable sponsons, I have to use stainless steel machine screws. But, I use no metal structurally - only epoxy & fiber glass.
A purist? No, just odd. As I said, I don't like moving parts, either. (Moving parts don't, and leak proof tanks do.)
But, I would recommend that you use whatever suits you. A nice thing about building our own boats is that, we can use many options that WE prefer. To heck with what someone else likes.