Even if you have a high-end 64-bit PC, many background processes and older games are compiled in 32-bit code. They cannot "see" the x64 libraries, making the x86 redistributable mandatory.
applications. These leverage more modern processing power and memory, but they only work on 64-bit operating systems. Stack Overflow Why You Should Keep Both
Visual C++ Redistributable (VCR)
It is not a choice of one over the other; rather, it is about compatibility with your applications: If you have 64-bit Windows : You should generally have