Looking at the statistics that are used to measure growth and performance at a population level are such a great window into how they themselves are opinionated stances.
The two measures are both great measures of house ownership that measure different things. The article frames the second one as better, and if you are looking to see the ownership proportion of people (for example as they note to look at the numbers of young people who live with parents) thats great. If however you care about the housing development decisions that will incentivise owner occupancy you might care more about the standard owner occupancy per household.
I often see this with respect to GDP/GDP per capita vs mean income and other economic measures, but its great to see a non economic measure like this compared in this way.