If you're thinking along the line of a Star Trek 'replicator', I doubt very much that there will ever be enough economical energy available to create matter on a macroscopic scale, let alone manipulate it into a useful form.
Run it through your 'e=mc^2' in reverse, and you'll see what's involved. You need something like 25,000,000 kWh (after efficiency losses) to create one gram of matter.
Energy is converted into matter all the time. Energy quanta carry inertia. Inertia, or mass, is the measure of the quantity of matter. Every time an atom absorbs a photon, energy is "converted" into matter.
I think what you are talking about is creating new matter particles from energy particles. The purpose of this experiment at Stanford is merely to show that matter particles can be created from energy, in order to gain a better understanding of the fundamental nature of matter. There is no suggestion that it has any practical purpose.There is no shortage of matter particles on earth. Why, on earth, would we want to use precious energy resources to produce new particles?
15 billions years ago our universe creates great amount of masses from enormous energy to us. Now, although we are in no shortage of mass, does that mean we should drop the idea of creating masses on our own hands?
Masses are abundant but not all precious. Many wastes are produced along with large amount of heat and light. Just imagine, if we can store the energy (such as unuserable heat and light) in a "package" of mass, and then reuse or unwrap the package to gain useable energy, that will be too great.
On my personal note, the nature and essence of our destination in the world of universe is to understand the process of energy to mass and mass to energy as well. This is the universal theme hidden in darkside of the power. It is miracle.
Einstein is famous for the law "E=m*c2", however is there a equation of somewhat "M=e/(c2)" and what does that mean?