Why should you program in C?
Ease of use
SysRPL is only found on HP calculators, and it is not trivial to master. Being stack based, it is very different from most languages. C is an industry standard, with only a few HP specific things to learn. Experienced programmers can apply their knowledge without the burden of learning a whole new programming language.
The most commonly used language for advanced programming is ‘System RPL’, or ‘SysRPL’. On modern calculators, SysRPL is mostly executed by an emulated ‘Saturn’ processor. C on the other hand is executed directly by the ARM chip. The same program written in C will be many (up to 100) times faster than the equivalent SysRPL program.
There are many things that can be controlled via a C program, but not by a SysRPL program. For instance, a C program could alter the CPU speed, display flicker-less grayscale, or control the beeper precisely. A pure sysRPL program could not.