This is very nice as it addresses the zero-index nature of time by going 0-23 instead of 1-24. Time would be much more comprehensible if all clock were marked that way.
Ok, it is interesting that the top of 12h clocks in those countries is often a 12 instead of a zero [0]. Maybe the tension of a cardinal zero in an ordinal world (i.e. 1900 is the 20th century) lead the Swiss Railway to de-number the 12h clock [1].
