The obligation described in section 21 is absolute. If the conditions are met, the type of decision does not matter. The obligation applies to any discussion. It is not just about decisions. Let me read the section, which is four lines long:
21 A public office holder shall recuse himself or herself from any discussion, decision, debate or vote on any matter in respect of which he or she would be in a conflict of interest.
In other words, this applies to any decision, discussion, and so on, regardless of the relative importance of the issue.