Aid climbing is one of many different types of climbing.
In Aid climbing one can hang from gear and pull up on it. Although a trad climber might treat you with suspicion, the motivation behind aid climbing becomes clear when you know what it is that aid climbers climb.
They climb incredably big pieces of rock, such as Half Dome in Yosemite, or
big crags on Baffin Island in the arctic.
These climbs can take many days to complete. The climbers live on a portaledge which they drag after them.
Three days up the side of the cliff, if you meet a large overhang which is impossible to climb free then you must Aid or retreat.
Aid climbers have their very own set of tools and ways about them.