I think you have heard from witnesses, people like Arend Lijphart, who have studied it pretty closely and have said that coalition governments in many places work very effectively and they can lead to governance that is as good as or better than what you have under first past the post.
It's also useful to point out that the larger political parties that have held power in our country have typically been, internally, coalitions of a sort. They bring together different viewpoints and factions. We can say that under first past the post, the large parties that we have probably have more of a coalition quality to them than do the larger parties under PR, because under PR, the smaller factions can more readily split away to form their own party and more fully express their factional view.
I suppose that might be part of the argument as well, as I say, that governing is always about working together with different groups in a coalition sort of format, whether that's the formal name or whether it's just more informal and tacit.