Anyone can benefit directly and indirectly. Usually when government can borrow more money, the can spend more of it to enhance the standards of living such as infrastructure. As a result of this mass purchase, people can capitalize on public stock and securities.
All evolution takes place from pressures from the outside. How else do they evolve? And it's not only through legislation. We started with a full reserve system until many bankers simultaneously implemented this fractional system since they knew the benefits of having a larger supply of money.
There has been much criticism on this. Use google to see.