Here we list a few of them. There are no safe seats With single member electorates safe seats are common. Political parties generally put most of their efforts into trying to please the minority of voters that are in marginal seats. With multi-member electorates every seat is marginal and the parties must take more interest in the views of all voters. Voters also tend to take more interest in politics if their vote is more likely to actually change something.
Voters have more choice Major parties endorse several candidates for each multi-member electorate.
Voters can choose between parties and between different candidates from the same party. This is obviously a good thing for democracy, whether the elected body is the parliament of a large country of the executive of a small organisation.