Durability is not only about connections between parts. Watch parts are prepared to work in a special way - each of them has some function in mechanism. Even if these metal elements are very hard, they are also thin and simply fragile. Prepared to work as a part of mechanism, not to be bested head of miniature creature.
Some bigger elements are definitely easier to use...
About techniques secrets: I make it carefully
There is a few people who try to make copies of my projects, so I don't "sell" my technology - all that I can do now took me nearly 6 years of learning, testing and trying...