I come from the systems research world. I've seen people choose C not for the reasons you mention, but just because it's what they know best. This is not always the best thing to do.

One instance is a colleague who needed to do data post-processing, and just did it in C because it was most familiar. A language like Perl or Python would have been a better choice, and saved him time in the long run, since string manipulation in C is tedious and error prone.