"The sound is a form of feedback. On modern laptop keyboards there is so little feedback that every bit counts. The sound is like a reassurance. It’s your computer telling you, yes, you did indeed hit that key."

Oh, feedback like say...

* a character appearing on the screen?

-or-

* the action you were attempting to effect happening

I have a few twee coworkers who insist on using these obnoxious things. Worse even than the physical keyboards, and their arguably beneficial tactile feedback, this is exclusively the worst attribute of these. Why would anyone who isn't basically cos-playing on a computer want this trash?