It's unclear, but it seems like this was someone testing to see if this exploit would really work. From the article:
> The severity was debated - Endor Labs characterised the payload as closer to a proof-of-concept than a weaponised attack - but the mechanism is what matters. The next payload will not be a proof-of-concept.
But it does seem odd not to use an actual payload right away.
I'm in the process of doing something similar but just planning on throwing them on my Immich instance once they're ready (and that lets me share them with other people as well with the Immich account management).
I was under the impression that Ubuntu Touch worked just fine with the Fairphone 5 which is very much not a "7-year-old out-of-production device". I'm currently writing this from a Fairphone 4 (with CalyxOS, not Ubuntu Touch though).
But it does seem odd not to use an actual payload right away.