I have a hand held mixer similar to the one here,
The egg beaters are straight forward, but what do people typically use the swirling attachments for? Do they put less air into the mixture??
These are dough hooks. They are used to knead yeast dough. They are useful, especially if you are trying to work with higher hydration dough which sticks in hand kneading, but many handheld mixers don't actually have the torque needed to knead dough, so if you need them, make sure to buy a good model which can get the task done.