I defer to the knowledge and experience of the professional property people on this forum but..
...why does everybody who has posted so far look at this as nothing more than a bricks-and-mortar deal?
I wouldn't expect foreigners - foreigners to Argentina, that is - to know that much about María Amalia Fortabat but she's part of the modern history of Buenos Aires and in her time was hardly ever out of the news - and not always in a good way. Think of her as an Argentine equivalent of the sister of the late Queen Elizabeth of the UK - Princess Margaret - and you are probably on the right track. I contend that whoever buys that property will be buying it for the legends and the myths and the scandals and not for number of square metres or the nature of the window frames. That's my opinion of why it's priced as it is.
Back in Dear Old Blighty there are some wonderful buildings. There are also, still, some awful slums which are rotting away on the edges of industrial towns and when they come up for sale - usually by auction - they often go for as little as £40,000/$50,000. There's a street in a rough end of Liverpool where in recent years three dilapidated houses came up for sale in quick sucession. The first one sold for about £50,000 which was probably a bit much because the one next door only fetched £35,000. But the one next door to that one sold for..
...£175,000 or about $245,000.
Why was that? It had once been lived in by a Beatle.