Once you're used to it, you can use the two separate clipboards independently. Say you wrote a sentence like, "one two five four three", you can correct it by selecting "three", cutting with Ctrl-X, then selecting "five" (meaning it is now in the selection buffer), hitting Ctrl-V to paste "three" from the clipboard, and then finally middle-click where you need to paste the "five".

I guess one could create shortcuts to a tool like wl-copy and wl-paste to either copy or paste content to primary selection (or regular clipboard for that matter). So in that case a simple script could run the command and in your desktop environment you setup a shortcut to run the script.

Yes its hacky, but in Linux nothing is impossible. :-) (unless it is...)

on some apps; it works with ctrl-shift-v. so ctrl-v for the clipboard, and ctrl-shift-v for the cut buffer.

In most programs, you can paste the primary selection with Shift+Insert