c is easily my favorite language of all time. even though i started with a much "easier" language (python), c is still my favorite language for big projects. python still has it's purpose, for things like quick hacks. despite this, i still often write scripts in c, considering most of my scripts run frequently or need to run very quickly. c is easily the best choice for things that need to be fast. for other languages like rust, i find that rust needs cargo and a bunch of other things to run, and i feel like the language is more complicated than c. c needs a compiler, and that's about it. as long as you have access to a compiler and the standard library you can write c code.
c is a small language compared to others, and is quite simple to learn. writing good c takes time, however. i'm certainly not a master at c, and sometimes i do write bad code. some of my scripts are hosted on this website.
a prime example of a script that needed to be written in c was my script that centers my cursor on startup of dwm. the script parses the output of xrandr, computes the values, and sets the cursor the center of the primary monitor. this would be fast enough on it's own in most other languages, but considering that it is done during startup of my window manager and the x server, it must be done much quicker, otherwise it may take way longer for the cursor to actually center itself. the code is pretty convoluted, since operations like converting strings to integers and splitting strings are a little more complicated in c than in python, but can be done much faster. you can view the script here.