In general, unless you feel sure that an insurance company is significantly underestimating your risk of a claim, insurance on something you can likely self-insure is not a good practice, and something that on average, in the long run, you will lose financially on (otherwise, insurance companies would go under).
Insurance makes sense when the event you are insuring against is a major hardship that you cannot easily ride out. Like a house fire/flood, or major illness, or an expensive car accident, or the financial burden of being sued. A broken or stolen bike does not fit that description. Even a $5K one (which will be worth much less in a year or two). You are probably far better of taking whatever premiums they are charging and stick in your own rainy day fund.
Just my $0.02.