In regards to the fact that Karl's lawyer made a really shitty defense of him during the trial and couldn't even bring up the right defense, I've heard some rumors. So in terms of statistics, what I've heard is that people have found that the odds of winning a lawsuit against someone in Australia as an American are disproportionately high because Australian lawyers fucking suck and America is the king country of litigious assholes (see: Billy Mitchell, Acerthorn, Russell Greer).
In addition to this ^ it has also been rumored online that Karl got the cheapest lawyer he could in Australia, because as he said in his vid he wanted to just beat Billy in court and force him to pay his court costs. Which even for a cheap lawyer would still be high given the timeframe of this lawsuit, but having a cheaper lawyer probably made the start up cost of this whole thing easier. So what we're looking at here is an immense hubris running full force into the wall that is America's force of bloodthirsty lawyers.