Why are consumer grade heart rate monitors not tested against 3 channel ECG devices which meet the requirements for gold standard for heart rate measurements?

The Schiller medilog AR was introduced by Schiller medical Switzerland in 2019, shown at 1 min in the video: And meets the requiremenst of gold standard for heart rate measurements as described here: But the Polar H10 does not meet the requirements for gold standart of heart rate measurement, as claimed in the paper: «RR …