234uW/cm² is pretty good, although it would be nice to see a response curve based on deflection angle, rate of deflection, and any data on how much energy it’s getting from the triboelectric effects (if it’s even 1% of the total).
The tough part for wearables is going to be energy storage. Even if you’re willing to put a lithium ion battery in a pouch sewn into a shirt near the small of your back, the intermittent power from energy harvesting sources like these are unsuitable to charge it. You need a significant capacitor bank to absorb those spikes and regulate the charge down to a point where a battery management system can safely charge the battery. Then you’ll need to integrate an impact resistant case into the garment so the cell doesn’t get perforated and explode.