It's kinda weird that VirtualPC way back when is the only VM software I recall using that had copy-paste without guest extensions. Granted, it just typed text into the keyboard, but it was really handy none the less.
That is indeed a problem :-) I had to bump up the delay between characters and particularly slow connections or serial consoles still can bite me. Mostly I still consider it worth using though, since fixing a few small typos is less work than typing the whole thing by hand.