It appears that Greg A. Woods <tuhs(a)tuhs.org> said:
I think one of the most loved innovations C (and B just
before it)
brought to programming languages was the use of braces instead of
begin/end, along with the elimination of some of the other extra
unnecessary keywords like "then". ...
I suspect that's because they came along just late enough that
everything used ASCII, and they got those cool Model 37 Teletypes, so
they could assume that devices could generate and print punctuation
like { } [ ] | < >
The C standards used to have (still have?) trigraph equivalents for much
of the punctuation for people on systems that don't have the characters.
R's,
John