Imagine a binary-only distribution of some application that runs on all hardware platforms (because we get that a lot in OS X and we used to get it on NeXTSTEP as well).
Proprietary software uses binary formats, yes, but interchanging 'proprietary' with 'binary' is a bit confusing.
Imagine a binary-only distribution of some application that runs on all hardware platforms (because we get that a lot in OS X and we used to get it on NeXTSTEP as well).