Text messages and emails allow the recipient to handle them on their terms. You can pick them up when you are not doing something else, you can re-read them, you can lookup information, you can put thought on a reply. A phone call will interrupt whatever the recipient is doing and put them on the spot.
Not necessarily, when you target one very specific setup you can use performance tricks you can’t use otherwise. When developing for PC you are forced to play by the rules because you can’t rely on a quirk of a particular combination of components because everyone has a different one.