That counts against you because now you have even fewer keys to work with to add copy/paste, shouldn't that extra physical key be instead used for those extra useful letters?
> First we have a large caps lock key and two alt keys.
My "Status quo" is using them for other better things. And right alt is also currently use for those non-ascii Europeans, so that's not an easy win. Caps lock might be, the current default is a disgraceful waste. So that only leaves Paste
> Even if in the scroll lock/pause-break region
Again, you don't have it on laptops, that's the main source of space constraints, so now you don't have universal muscle memory experience.
> With this option you could keep Ctrl+C/V
Hm, yeah, I thought of a universal replacement.