A shoe is made of many seams, not just the sole seam. A seam always requires a perforation in the material where the thread passes through. However, the big advantage of rubber is that the perforations in the sole immediately close again. In addition, we use polyamide as a yarn type, which does not transmit moisture. So, you do not have to worry about getting wet feet through the seams in our soles.
On the contrary, with non-sewn shoes, the adhesive often softens due to moisture. You can see that when you look at "normal" shoes in the seam area. Often, after just a few weeks, the sole comes away from the upper.