Because someone asked "how can we make the Apache/pilot combination even better?"
Then some other geek said, "Well, wait...how about we combine this virtual simsense with the pilot's own sensations to radically improve performance and survivability?"
A lot of scientific and technological innovation has come from, "what happens when we do this?"
Subsequently followed by, "what the hell, let's give it a shot!"

The academic version of, "hey y'all, watch this!"
-Siege