Why Choose a Wire Like Clapton Over a Single Strand Wire for Coil Building?

Exotic wires have an advantage over single strand wires in two fundamental ways.

The structure of exotic wire have more surface area to interact with the e-liquid. This allows a more potent pull of vapor which improves, among many things, the flavor profile of your juice. (Please note that only low nicotine juices are recommended when using exotic wire at a low ohm due to intake of unintended nicotine overdose.).
Another advantage of exotic wire is the amount of surface interruption it has. This means that the wire itself is able to act as a wicking medium for the juice to settle in. Like the first example i stated, this advantage brings out optimal flavor and overall potency of the pull.
Also to note, it's much more fun to build with the many types of exotic wire that's available. It's only of things in life that is both visually appealing and better in function at the same time.