Every phone I've used (except the first) has been modal - you have to look at the screen to see what it's done. Is it asleep? Is it in screen-saver? Has an alarm gone off?
The first phone I ad I could drive without looking. every other phone I first have to see what it thinks is happening, before I have a conversation.
And it reacts differently according to stuff I can't always know, such as whether a message has arrived, or similar.
Phone interfaces would need substantial changes for this to work, changes I'd like to see. I hate the modality.