A bigger UX problem (on Linux) imo is the multitude of clipboards, we have x11, vim... Those can be synchronized or not, they manifest different behaviors...
And btw while apple is often offered as some golden standard for key bindings, I think the situation there is much (MUCH) worse: apps often intercept and handle common combinations on their own, with unclear precedence, which leads to non-deterministic behavior and a complete mess if you want to override any standard combination.
The clipboard has always been annoying. Even today, you often see a "copy to clipboard" or something on a web page, and it never works on Linux. Not as I've got it configured, in any case.
Edit: Hmm, got one already called clipman, and it can display the two types of selections, now just have to figure out how to use it.