My understanding of the shoulder belt is that it has to do with angle of the seats. On the A330, due to the narrower cabin, the seats are angled further forward compared to the 787 and especially the 777. This leads to the need for the shoulder belt. Other carriers do have shoulder belts on versions of this seat installed on multiple different aircraft, so it is also likely that this is a newer version of the seat. Hopefully they have fixed the deflating issue with this version (hard to imagine they haven't but you never know).

Even better is that it does appear they have fit 32 rather than 28 seats in the business cabin. This will mean 2 extra seats for upgrade potential compared with the 789. I suspect we will see these on a number of transatlantic flights (especially LHR from YUL and potentially YYC). It will be interesting to see the number of PY the aircraft ultimately have.