From the article:

“It’s not the first cell, it’s not the first microbe, it’s not the first anything, really,” said Greg Fournier, an evolutionary biologist at the Massachusetts Institute of Technology.

Article also says:

"LUCA is the furthest point in evolutionary history that we can glimpse by working backward from what’s alive today."

Which translates to: first in time, IMO

But my point was: LUCA described here is realy complicated so why it makes some new quality ? Maybe some milestone, yes.