Except they very much weren't, were they? They differed enormously in distance, demography, geography, infrastructure, points of access, and a hundred other factors that helped or hindered their ability to respond.
"Probably"? It factually doesn't: regardless of covid, the UK experiences excess winter deaths ~20%+ higher than Sweden does, for the same years.
Interestingly, the very academic who provided the much-cited figures purporting to show how much better Sweden did... also provided an alternative set of figures that adjusts for the demographic differences between the Nordic countries. And they show the excess mortality rates are almost the same. He also notes that the 'success story' fails to factor in that Sweden had been experiencing a declining excess death rate for many years before covid. So, essentially just what I was saying: other factors can account for this, and you can't just look at these figures in isolation.
No, the WHO says it's the better method for assessing the impact of the pandemic, not the success of a public health policy.