What difference does it make when worn that the toe seam thickness is described as under 0.4mm?

Looking first at the figure of under 0.4mm, it is a specification that precisely reduces the thickness of the toe seam^[1]. nozzle quiz's Anti-slip Fivefingers Socks are socks made for trail running and hiking where one goes up and down rugged mountain trails^[2].

The automatic looping seam applied to the toe is a method that tightly meshes and connects the loops of the knit fabric to finish it without a bulging seam ridge. The thick toe seams of ordinary socks easily press against the skin and cause blisters by rubbing against the inside of the shoe when running or walking downhill for a long time. These socks reduce the pressure of the ridge transmitted to the tips of the toes by thinly finishing the toe seam thickness to under 0.4mm^[3].

In addition, an independent cutting structure that wraps each of the five toes separately was added, relieving the friction and blistering caused by the toes touching one another^[4]. Japanese patented non-slip yarn is wrapped around the entire sole of the foot, providing grip so that the foot does not slip inside the shoe and reducing the feeling of foreign matter^[5]. Starting from refining the minute seam thickness, it ultimately leads to relieving the fatigue that accumulates in the feet throughout a long mountain trek.