Insurance prices are usually based on the maximum possible loss as well as the probability of loss. Insuring only the online bitcoins means your maximum loss is

Insurance prices are usually based on the maximum possible loss as well as the probability of loss. Insuring only the online bitcoins means your maximum loss is 50 times less than if you had insured all. Insurance will be much cheaper. You argue that the probability of loss of the offline bitcoins should be much smaller, but I don't think insurance companies will go along with this argument. Insurance companies are skeptical and conservative by nature. And they have absolutely no trust in human beings. And from the point of view of human intervention offline bitcoins are about as vulnerable as online ones.