General question, but why do window wall systems always need the thin ventilation piece above the windows whereas curtain wall systems don’t?
The renders rarely show those pieces but they have a large impact on the look of the glass.
Residential curtain wall does include vents, but they're often better integrated, or even hid behind the balconies. I'm not sure how commercial towers manage to avoid them completely, but I would presume that they have significantly different ventilation systems.
Here are some examples of residential towers with curtain wall, with varying degrees of vents.
For instance, the Four Seasons (shorter) tower shows them quite prominently:
Google Maps
Or Monde, where they're a bit more subtle, but still there:
Google Maps
Or One Bloor East, where they are supremely well hidden to the point of only being able to see some on the podium:
Google Maps