I worked on a team that produced a distributed tracing library. We were tasked with interoperating with OpenTelemetry, or at least figuring out what that means.

My teammate said that at a previous job he wanted to add OpenTelemetry tracing to some C++ code he was working on. He took one look at the reference implementation for C++ OpenTelemetry and decided instead to write his own tracing library that sends gRPC to the OpenTelemetry collector.

It's also worth noting that, at least last time I checked, the reference implementations per programming language are less like reference implementations of some specification, and more like "this is the code you use to do OpenTelemetry in this language."