Living in an MMP country, I can say I think the party list system truly sucks, because you get career politicians that you can’t vote out, whom are essentially elected by themselves into the party.

I think one of the most important strengths of democracy is voting out people we don’t like, and MMP badly breaks that ability.

The argument for the list is when 5% of the population would vote for NZ First, and Winston Peters would get a seat because he put himself first on his party list. He would get over-representative power when a coalition government was required: in that specific situation he had a constituency. However in the larger parties (National, Labour) there are situations where people on their list get in on their party vote, even though the person is wildly disliked in the electorates, and would never get a constituency. During a past landslide Labour win, a bunch of nobodies wayyyy down the list (not expected to ever win) got in as members of parliament with zero constituency.