Why Windows 8.1 64 bits is better than 32 bit?

The terms 32-bit and 64-bit refer to the way a computer's processor (also called a CPU), handles information. The 64-bit version of Windows handles large amounts of random access memory (RAM) more effectively than a 32-bit system.

I wouldn't say "all" the games, but if you have the required components to play the games, such as a good graphics card and a lot of ram, then sure.

If you have a 64 bit computer and use 32 bit only half the data bus lines in the motherboard architect will be used. 32 bit can not access all 64 data bus lines. It is inefficient.

Because you can utilize 3+ gb of ram.

64 bit machines cannot run 16 bit games natively.