The researchers are still a ways away from the debut of "functional textiles", as they term the burgeoning field of smart clothing. Integrating conductive threads in attire is promising, and could lead to smart clothing that does what real circuitry does: Gathering, storing, or transmitting data. Shirts could act as antennas for smartphones, workout gear could monitor health, and hats could monitor brain activity.
The latter could be a more lightweight and comfortable alternative to bulky external wiring for brain-tracking experiments, like this proposal that needs brain activity tracked for implants that would treat brain conditions like epilepsy and addiction.
And stitching circuitry is essentially the same as stitching thread. In one lab, researchers use tabletop sewing machines and swap in fine silver metal wire for thread. It's the shape of the embroidery that determines the frequency of operation of the antenna or circuit. The photo above, for example, is an intricate circular design that's great for antennas. Just like circuit printing, stitching is a versatile way to make ad-hoc designs.
Most importantly, those stitched antennas actually work: in tests, that circular design transmitted signals with near-perfect accuracy, and would be suitable for broadband internet or cellular communication. Wouldn't it be nice to wear a shirt that boosted your smartphone reception or transmitted more accurate health data?