I think it is easy to map \007 to the bell, since it is documented in lots
of manual pages.  It's a character, which maps to a tty result.

\a is a C mapping to a character 007 to an tty result.  It's two step.  It
is harder to find documentation on this, so I'm not surprised that \007 is
used more often, and I expect it will continue to keep re-arriving in all sorts
of source code.