You're focusing on my not knowing the syntax and specific of the languages. It's still just giving names to things that did not have a name. Whether the name is a variable name, a function name, a type name, doesn't matter.
It's still a fancy, obscure jargonish way of saying "name things".
In the example of that article, the only place that use the data structure is the when in the function that execute the data structure. A compiler may happily just inline it because no other where use it. And you lost no performance at all.
Or it may just decide to generate the result as it and you surely have performance problem now.
It's not a new trend, the first citation on wikipedia is to a paper in 1972.