Consensus decision making works best when there are real practical issue at hand and it isn't some politicized debate where people often prefer to put on an act for their in-group.
It is also important to recognize that in some cases the people with the most practical experience of the topic discussed might not be able to attend lengthy meetings due to more pressing issues at hand.
I found this a good overview: https://theanarchistlibrary.org/library/seeds-for-change-consensus-decision-making