Conan is a cooperate packaging framework, which obviously favors binary packages over source-only. And there's no guessing, all the options are hashed, and the binary is based on this hash. A single option change leads to different binaries.

Even in open source it's extremely important to use proper options (arch, flags, deps in which variant, ...). E.g. with something Debian or Redhat they decide on these options. With conan you can decide by yourself. E.g. use better hardening flags or a better libc or a more stable dependency package.