Good Post...I assume you are concluding this because they are predominately playing /laying the asian handicap market , and as a consequence their % over round is very small thus making it comparable/better that betfair(after commission) ?
Pinnacle do the same in the States for US sports. They realise that if they are the best price about both teams that you will take a massive amount of volume. This is obviously much harder to do with something like horseracing with a lot of runners but the model is still valid. Problem is that you have to have very good traders and odds compilers or else the low margins turn into a loss very easily and most firms just employ people with, at best, limited skills. By way of example I have an acquaintance who is the trading director of a big sportsbook nowadays. In an earlier role he was head of trading for a big US facing online sportsbook and they put up a prop on whether the coin toss would be heads or tails 10/11 each of two and took a fair bit of money on heads so he went 4/6 heads and 11/10 tails. When your head trader can make such fundamental mistakes as that you can't go 1.97 each of two on a football match!!!!