I fully understand your argument as to why a weather waiver may not be as successful or effective as it is in the US. I get that the route frequencies aren't the same..etc. However, nothing in your argument supports the idea that the airlines should not offer the option to their passengers. Just becuase they will have fewer options, does not mean it wouldn't be beneficial to lighten the loads with those willing to cancel, change dates, or change routes (where available). Also, as previously mentioned, it would also go a long way to customer service.

Bottom line, the cost of having a more liberal weather waiver policy is likely to be nil, and may actually save some time/money/headaches, even if only for a few.