The actual patent describes it as something like "catastrophic buckling" of the spring.
Here, the spring is not just something that creates pressure for the stem and up and down movement into position, it is the actual buckling of the spring that makes the activation happen.
I rarely bottom out my keys, except, that I tend to hit certain buttons particularly hard, most noticeably Return, Spacebar, period (when it is a full stop), Delete, and probably the arrow keys. There is sure to be a psychological reason for that, not a physical one.
When you get used to the keys, you will find that they are very easy and comfortable, bottoming out or not. And also, in my opinion, there is very little sound associated with bottoming out buckling spring switches.