Well, it has it’s good points and bad points.
On the bad side, some people don’t give a toss, so they either donkey vote (which is numbering your preferences 1,2,3,4,5 etc in a line down the page, which does count. So the parties always try and get themselves at the top of the ballot!) or they don’t vote properly, in which case their vote doesn’t count. Or they don’t vote at all. Like I said, the fine is minimal and rarely enforced. However, the amount of no shows is very small.
On the plus side, parties have to me very mainstream in their appeal or they will not have a hope. I’ve always thought that when voting is volunatary, most people won’t bother, and so pollies only have to appeal to the people who are going to vote, who are likely to be more extreme (because they ‘care’ more) like your gran, or your neighbour who calls the police whenever your dog is barking. Whereas in a compulsory system, Joe Bloggs has to vote, and he’s not going to vote for someone that wants to ban hoodies, for example, because Joe Bloggs rightly thinks that’s loony.
Also on the plus side, no one is disenfranchised. If I lived somewhere and there was only a 40% voter turnout, and they had FTFP, and the party that won had only 30%% of that vote, then my new rulers would have been selected by only 12% of the voting population - And that’s not really a democratic mandate, is it .
You could even call a volunatry system a form of oligarchy, the mandate is so small. And though I didn’t vote, my reasons for doing are not neccesarily apathy, especially if I was from a disadvantaged area. Or didn’t speak the language.