Quorra (and the ISOs) are described by Flynn as a "miracle" that can "change everything" in the human world
How can she help the human race when she's just an electronic signature in a computer and how can she even exist in the real world?
Quorra (and the ISOs) are described by Flynn as a "miracle" that can "change everything" in the human world
How can she help the human race when she's just an electronic signature in a computer and how can she even exist in the real world?
Though it's never actually mentioned in the movie, and is only shown on screen for a matter of seconds, there are actually tanks behind the laser assembly in the arcade basement. The writers have stated that those tanks contain things like water and carbon -- IOW, the building blocks for organic life. The premise -- admittedly farfetched -- is that the laser breaks down the matter, stores the pattern in the computer, and then can play it back out, reincorporating the organic materials in the correct order to rebuild the object/person.
Presumably, since Flynn had been working on the problem of bringing the ISOs out into the real world, the tanks were stocked with additional materials that would allow Quorra to be "built" in real space from the pattern in her "digital DNA".
As far as her helping the human race, Flynn believed that the optimizations in the ISOs code could translate into human DNA, allowing for genetic studies that could lead to gene therapies to eliminate disease, genetic conditions, and aging.
Your question is actually answered pretty well in the voiceover.
Flynn describes the ISOs (Isomorphic Algorithms) as being;
"an intelligence beyond our own"
and that their superior intelligence will lead to substantial advances in several areas;
Medicine
"Disease? History."
Critical Thinking
"Science, philosophy,"
A paradigm shift in human understanding of alien intelligences
"The possibilities of their root code, their digital DNA. Every idea man has ever had about the universe up for grabs."
when they're transferred into the real (human) world by the same scanning laser that digitised Flynn and his son.
I had a different take from both of the other answers, so I thought I'd share it, though it's a little more esoteric.
I'm a programmer. When I need to understand a system, I need to review its source code - this source code is the set of instructions which defines its behavior. If I don't have the source code, I can construct a model of it by observing its behavior, but this is time consuming, difficult and imperfect.
My impression from the narrative was that because the ISO's had arisen independently of Flynn's creation, their source code was vastly more similar to real life than the other programs. By examining their source code, you could make inferences about the source code of life (which is far deeper than mere DNA, we're talking the source code of existence) and thus make these great advances.
The ISOs were a group of programs that spontaneously appeared on the Grid. They were not programmed or created by users. They also differed from "regular" programs in several key ways:
ISOs differed from Basic programs in their appearance and capabilities, but their uniqueness lay in their code base. While regular programs conform to the rigid structure defined by their users, ISOs had evolved, complete with a genetic code of sorts that even Kevin Flynn could scarcely comprehend. This inner structure of their code would potentially have allowed ISOs to develop beyond the capabilities of regular programs.
Source: http://tron.wikia.com/wiki/ISO
Computer programs on the Grid, and in the real world, are limited by their programming. As ISOs were not programmed, but instead "appeared", they are not limited in the same way, and can revolutionize various fields by providing a new, non-human approach.