It is not because most of the world do summer time and that when they do they have a 1h transitions that we should take it for granted.
This article do not mention the Chatham Standard Time Zone from Chatham Islands archipelago in NZ which is 45 minutes ahead of New Zealand Daylight Time, nor the Central Western Standard Time (Australia/Eucla). Also wikipedia mention there is a "train timezone" for the Indian Pacific train. I wonder if other trains have a dedicated timezone?