One practical consequence of this is that you can't "escape" some delimiters to match literally, e.g.:
m$\$$ will treat $ as the end-of-line assertion (or as variable interpolation if $ is followed by an identifier), but there's no way to get it to match '$'.
But that's ok, as you can still use \x24, or even
\N{DOLLAR SIGN} after use charnames ":full";.
Imo, if you want to match a literal dollar sign in the regexp, you just should not
use a dollar sign if you want to match a literal dollar sign. That's the same
thing as /^\/usr\/bin\//-like regexps, or even worse.