CTF is just a specially compressed format and specification of embedding the source code into the binary; it's a complement to DWARF format, not the format itself. The documentation you cite even says it's similar, meaning that it's not DWARF.
The main purpose of CTF is to provide a succinct representation of the graph of C types used in a program. It's generated from DWARF; anything encoded in the CTF section can also be found in DWARF info. CTF has nothing to do with "embedding source code" and isn't useful for stack unwinding or symbol resolution.
