Digital displays draw a lot of energy, and need to be bright enough to be visible in direct sunlight. A more advanced version of this could increase the battery life of a camera substantially.
I got a used nikon from 2008 recently, with a bright lens, and am marveled how great it is. I was about to replace bad baterry, but honestly... Even a bad one thats easily 10 year old, gives me a solid week of fun.