One reason to learn C is to grasp the basic syntax and control structures that it shares with many languages in the same family.
For me, awk, PHP and JavaScript come to mind, but the list is rather long:
https://en.wikipedia.org/wiki/List_of_C-family_programming_l...
The 40 pages of Chapter 2 in The AWK Programming Language (first edition) is a superb introduction to the syntax and control structures in this family.
https://archive.org/download/pdfy-MgN0H1joIoDVoIC7/The_AWK_P...
Other reasons to use C are speed, control, and systems programming.