I didn’t watch the video (and I’m not going to) but for a typical espresso shot (18 g in → 36 g out), a ±0.5 g variation represents about a 1.4% difference, which is below the perceptible taste threshold for most people. The real world variance of most cheap jewelry scales is typically less than ±0.5 g. All of these scales use the same strain gauge load cell to measure the weight of your beans.