your 2nd and 3rd points are very questionable.

Very often Perl is more real-time than C.
Agree with me or not, but I saw several times a discussion when it appears that GCC is incapable to compile some large autogenerated programs, because it uses O(N*N) in many places. Therefore people bother splitting such sources to chunks.
Ideal programmer will create faster programs in C, but real-world programmers often write

for (i=0; i<strlen(s); i++) {
  // and never notice that counting lentgth is on every iteration
}
[download]

It is unrealistic to use advanced techniques on C everywhere,
in perl it is often hard to write bad: you often save precalculated values in hash, and so on.

As for 3rd item - embedding perl into different application is very common practice (well, cases when bytes count are exclusion, but those are rare, IMHO).