I work in this field and written papers on these objects, so I am aware of their significance. This is exactly why I left the comment for people to know whether that's something particularly novel or interesting (for non-experts) or not.
What's notable is less the faintness, and more the distance / proximity.
I don't know that this is the most distant very faint dwarf satellite observed, but it is the faintest orbiting the Andromeda galaxy, to date. That may speak to observations not possible with nearer VFDGs, or speak to new observational methods / techniques / equipment which made the observation possible.
I'd hope that someone working in the field (I do not) might be able to comment more substantively on such matters, rather than quibble over the relatively uninteresting fact that nearer VFDGs have been observed with far lower absolute luminosity, which ... is rather to be expected.
