That's a neat website, but it did confuse me for a moment. It's titled itself "metric time", but seems to be the same idea as detailed on the "Decimal time" Wikipedia article - https://en.wikipedia.org/wiki/Decimal_time.

However, that article warns to not confuse it with its own "Metric time" article, which isn't the same as that metric time website, it's just the SI units related to time - https://en.wikipedia.org/wiki/Metric_time.