There's also a huge variance in microphone quality for Android devices. The engineering focus to ensure uniform sound quality could take away from the team's focus in its early stages.
> I wonder if it was intentional or just a matter of priorisation.
I assume both? Intentionally prioritise iPhone over Android, because thats still (rightly or wrongly) considered the higher value platform to target. Instagram did this back when they launched in 2010 too.
Find it hard to believe it wasn't intentional. The class associations with iPhone are quite strong.