These TV’s have the capacity to “upconvert” the standard HD 720 - 1080 signal to something approaching 2 - 4K depending on the quality of the original signal. Translation = The existing picture it delivers will look a whole lot better than any regular 1080p TV. That is a good thing, especially when it comes to movies, sports, etc.
Practicality, is the keyword.
Nobody goes out to purchase a super-duper-HD-TV, just so they can have the sent signals upconverted to higher definition. Makes no sense to spend the extra dough that it would cost just for that.