First off, I don't think they are explicitly trying to fade out older messages. The received message bubbles are gray and don't seem to have a gradient effect going on; it's only the sent ones which are colored (green or blue) and have the gradient. So I think Apple's goal here really was just a gimmicky gradient effect for the colored (sent) messages.
More evidence for that is that the bubbles themselves don't seem to change colors as you scroll; rather they are just sort of a mask for an underlying gradient layer underneath (so you can have one large bubble which fills the screen and is light on top and dark on the bottom).
But even if their intention was to make older messages fade out, it was still severely misguided. It is trivial to discern which messages are older (they are higher in the chain and therefore further from the text input for a new message). Users of iOS have been familiar with this for years (and isn't the new UI supposed to move away from explicit visual cues since the assumption is people are used to it by now?).
Moreover, it actually hurts usability, since users now have to scroll more often to get messages in the readable portion of the screen if they want to read through a conversation.
And, on top of all that, if there is only one sent message in the conversation, there is actually no way to bring it into the readable portion of the screen due to the snap-back! (Further evidence that this was intended to be no more than a visual gimmick.)
First off, I don't think they are explicitly trying to fade out older messages. The received message bubbles are gray and don't seem to have a gradient effect going on; it's only the sent ones which are colored (green or blue) and have the gradient. So I think Apple's goal here really was just a gimmicky gradient effect for the colored (sent) messages.
More evidence for that is that the bubbles themselves don't seem to change colors as you scroll; rather they are just sort of a mask for an underlying gradient layer underneath (so you can have one large bubble which fills the screen and is light on top and dark on the bottom).
But even if their intention was to make older messages fade out, it was still severely misguided. It is trivial to discern which messages are older (they are higher in the chain and therefore further from the text input for a new message). Users of iOS have been familiar with this for years (and isn't the new UI supposed to move away from explicit visual cues since the assumption is people are used to it by now?).
Moreover, it actually hurts usability, since users now have to scroll more often to get messages in the readable portion of the screen if they want to read through a conversation.
And, on top of all that, if there is only one sent message in the conversation, there is actually no way to bring it into the readable portion of the screen due to the snap-back! (Further evidence that this was intended to be no more than a visual gimmick.)