If ou had a fragment with both HEbrew and Aramaic, or with Hebrew where MT has Aramaic or Aramaic where MT has Hebrew, etc. that would be interesting. But, simply a fragment from one section of the book tells you that that section of the book, or its forerunner, or a parallel, or a later version, existed. Look at the so-called PRiestly blessing amulet from Keteph Hinom. What one can not learn is that Numbers 5 or 7 did not exist at the time. SO it is with the Ezra fragment.
Fragments are fragments.