It's reason enough for me to stick with Firefox.
Elsewhere I either double-click on a word, which will select that word for pasting, or I mark a section with the left button (press and hold at the beginning of the selection, move and release). And the middle button will paste. And paste again, if I wish.
But URLs in Chrome-based browsers instead behave in the annoying way described above. In the past it worked as expected.
If your mental model of clipboard interaction only involves a single clipboard, and you use X, your mental model is simply wrong.
Sure, you could change X to match your mental model, but now you've broken the mental models of everyone who actually learned to use the software. And one more useful feature that makes X nice to use gets sacrificed to please the people who came from Windows but desperately want everything to work like Windows.
Any time I've seen someone do it it's: mouse to select, keyboard to copy, mouse to select other place, keyboard to paste.
I cringe every time because it could be just: mouse to select, mouse to select and paste it in the other place with one click.