Haha, well true, but not only is ко a real word that is used, it has the same meaning in every way. It IS the same thing really, just a modified realization of it.
For instance, only in speech, when in English we shorten "of" to a short "o", it always miraculously makes sense, even when you'd be shoving to vowels next to each other.
/It's the end o' everything./ Not something that anyone'd ever write, but it sounds perfectly understandable. Honestly, I probably don't pronounce the f in of more often than I do! Granted, I slouch my speech more than I ought to.

Even look at "a" versus "an".

/It is just an joke./

Sounds weird as hell, but I still would still totally get it. My first thought would just be "why?".

The Russian rules for when to us which form are clearly more complex, one might go so far to say "blurry". So I'd assume the two forms would really really blend in use, or at least allow swapping occasionally.