The Apple 64-bit A7 chip is necessary for the company and it is meaningful that Apple got there first. The A7 chip has: 64-bit desktop-class architecture, modern instruction set, 2X general-purpose registers, and 2X floating-point registers. The Apple A7 is the first processor from any company to implement the new 64-bit ARMv8 instruction set. The ARM in ARMv8 is referring to the dominant chip technology used in smartphones and tablets worldwide. The v8 part is referring to the ARM 64-bit chip architecture and all the current ARM chips are 32-bit.
The 64-bit allows data-intensive applications to handle large data more efficiently than 32-bit. The only other ARMv8 chip that is close to it is Applied Micro's X-Gene. Apple will have to convince its own developers that it makes sense to develop 64-bit apps for consumers. We won't be seeing 64-bit apps anytime soon but might have a chance in the near future. Not many apps will benefit from the 64-bit processor. The iPad for sure will be going to the 64-bit A7 chip, so there is a more potential for future iOS devices that Apple is undoubtedly planning. All in all, this seems to be a great step forward with Apple and trying to make their devices better and faster.