Until I came to wikitree I had never encountered in genealogy, the use of United Kingdom, as an identifier that should be used in place names after England, Scotland, Wales or Northern Ireland. I personally don't think it adds anything, however I do think that it is beneficial to have a tidy uniform implementation of a United Kingdom policy.
I also want to say that the use of time period dependent country naming policy is confusing to people who have limited knowledge of the history of a certain area.
For example I live in Brisbane, Queensland, Australia. Everybody should have a fair idea where that is.
Australia is a federation of Sovereign states. The Colony of Queensland was a sovereign entity created by a Monarchial Parliamentary Constitution granted to it by Queen Victoria after two Acts was passed by the British Parliament.[see]
So when I'm adding a place name to a profile for a pioneer of this 'area' is the town Brisbane or Moreton Bay? Was that in the 'state' or colony of Queensland or New South Wales? Or was that the country of Queensland or New South Wales? Without a very good knowledge of the history of the place we can't even know what the continent was called - was it Sahul, Gandwana, Nova Hollandia (New Hollande), Terra Australis, or Australia. And I haven't even tried to canvass the Aboriginal names for the area.
Take for instance the death of Patrick Logan. Wikipedia says he died October 1830 near Mount Beppo and was buried at Surry Hills, Sydney (which is in New South Wales) His death is registered by the New South Wales Government but where is Mount Beppo? "Mount Beppo, Queensland, Australia" is a place name now but none of various parts were in use then. There was no Hill nor locality named at that time Mt Beppo. There was no state nor colony of Queensland in 1830. There was no Sovereign country named Australia. Wikipeadia tells us that 'The first official published use of the term Australia came with the 1830 publication of "The Australia Directory" ' but was that before or after Patrick Logan died? "Mount Beppo, New South Wales, Australia" was never a place name, neither was "Mount Beppo, Colony of New South Wales". Where he died would have had at that time an aboriginal place name, district name and tribal area name but you won't find them listed in any historical documents. So... what would I use... "Mount Beppo, Queensland, Australia" - because I know that is the best descriptor of where he died (nb. Mount Beppo is both a hill and a surrounding locality.)
What about Birth, Marriages, and Death registrations. If pioneer profile encountered such an event during a certain time period of our history, you can find his BDM event registered in both the BDM indexes of the "Government of New South Wales, Australia" and the "Government of Queensland, Australia"