Yes - this is unfortunate, as the degree of proportionality is obviously higher in a 5 or 4 seat constituency than it is in a 3 seat one.  However dividing the country into regional constituencies does preserve a local element to the election, there is more of a chance than you know at least some of the candidates personally, and there is thus less of a tendency to promote "celebrity" candidates for their name recognition alone.

A key feature of the system - unlike the UK first past the post one - is that there is almost no such thing as a wasted vote.  Unless you only indicate a preference for a few very marginal candidates, your vote ends up electing someone, even if it isn't your first choice.  Thuis there is no such thing as a "safe" constituency where there is little point in voting because e.g. a  Labour, or Tory candidate is sure to win in any case.

Lots of people vote tactically - voting for minor candidates who they know won't be elected but whom they want to encourage, but then ensuring their vote ends up electing the least unacceptable mainstream candidate.

notes from no w here