RE: Any practical use for Universal Common Ancestor?
No, because Science has not designed the right model of UCA, yet. Are there any scientific practical use for your parents as the common ancestor species of you and yours brothers? You had the shape of an unique initial cell as also the shape of the initial cell after abiogenesis; you had the shape of fetus as the shape of reptilians: the shape of embryo as the shape of mammals. But, your parents as your UCA never existed inside yours little ovule universe during yours embryogenesis. So why the UCA of the first cell should be at Earth during abiogenesis?
So, the design of the model for UCA is not for Biology or Physics, it is for Astronomy, the space beyond this little egg-Earth, like your mother´s body was the space beyond your little egg. And why Astronomy did´n it yet? It happens that Academic Astronomy did not get the right theoretical model of astronomic systems, the formation of astros, etc, because the academy is under magical thinking: magic accidents which, instead destroying things, build on new complex things. Like any other non-existent magical gods.
Comparative anatomy between the last most evolved astronomic system from Cosmological Evolution and the first cell-biological system from Biological Evolution must be the unique rational and right method for finding the right model of UCA. I did it, I got a model, I don´t know if it is right, need more testing. But, if it is right, will be very, very useful not only for practical science and new technologies, meaning more useful for eliminating magical thinking from human mind.
It is weird thinking to make comparisons between living and non-living systems. I thought that also, till find that there is no such division between living and non-living when talking about natural systems: all properties of cells are there, working, at the right model of astronomic systems. And there where no "origins of life", neither here neither other place, there are no "origins", every natural system is under transformation from pre-existing systems, and evolution. The words "origins" and "life" are big prejudices to rationality because they lead us towards magical thinking with all the prejudices to humankind. Ok, mine is merely another theory, so...
There was no origins of life and universe, astronomical systems are half-alive, light waves contains the code for life and DNA is not a code: Matrix/DNA Theory