Typing on mouse switches would be really bad for your fingers. Basically like bashing your fingertips on a solid surface due to the tiny travel distance. Would possibly harm the nerves, etc.
What you say is true, but if you look at the video about the switches on this Tim Tyler's website, the switches he uses are like 5 times the size of a regular mouse switch, like the typical Omron switches found in say, a Razer or Logitech mouse. The give is much more ... giving, with the switches he uses. He actually noted in the summary video that he would want to work on
decreasing travel distance, were he to design another keyboard.
The thing about this idea is, the concept of the switches he is using, is on a very high level, similar to buckling springs. A piece of metal has pressure applied to it until it "buckles" therein actuating the contact. These switches look VERY easy to bend / mess up somehow, and definitely don't look as durable as regular BS switches.
That being said.... If somebody really liked buckling springs, but just wanted a lighter actuation force, this is probably the closest to that dream as you can get.