Despite the ranting of the TAB's (and their mouthpieces) the nett effect to the Aussie punter of Tassie granting a licence to Betfair will be IMHO - Sweet F.A.
The punter (gambler really) who sits in the pub on a Saturday will not suddenly spend his day at home in front of the computer betting and laying in every race that appears on the TV.
The more sophisticated punter and those with a vested interest (e.g. the bookies) are already using Betfair - no change again.
If the TAB's decide (or are compelled) to reduce their % takeouts it would be great but I am not holding my breathe. If they do it will probably be a small reduction in the Win/Place % offset by an increase in the exotics %'s where Betfair doesn't compete.