Waiting
Another purpose for a sub to be put into a certain position is to wait for the next thing to happen... for example, You as Dom(me) get a phonecall, then you can put Your sub in a waiting/holding position as shown below by subgirl.
The Dom(me) can also combine waiting positions with a slight form of punishment - although there are other (harder) positions to use as punishment. To use the waiting positions as punishment, You can just tell Your sub to "wait" with his/her nose against a wall, and with speech restriction. As I said, it's a form of punishment which isn't too hard - physically - but it will leave mental marks... and it will be kept in mind for quite some time.