Also preferential voting means you can actually vote for the candidates you want (you can’t ‘waste’ your vote by voting for someone other than the big two parties like in US), and (afaik) when your do this, and a candidate wins based on your lower preferences, that candidate gets data on what your first preferences were (so e.g. they know that a certain percentage of my voters had a higher preference for this other party, which means next time around I should possibly consider adopting some policy from this other party).

(I might have gotten some details wrong, someone feel free to correct me)