True, they are mostly for show. But if they are able to be preformed on a unmanned player2 dummy, then given the right situation, they should be able to be preformed on an active opponent.
As you said, if you screw up, then it will leave you wide open for a counter, but that's the price you pay for attempting such a bold move. You would have to be very talented and equally lucky to pull something like this off in mid-match, but then again, that goes for most good kombos, not just the over the top ones that appear in these kind of videos.