D.S.
We are using them after our city "endorsed" them last year as well. I called my insurance agent for his advice and he was aware of them. He felt that my neighborhood was a good fit for the service and the price was reasonable, so we purchased it. A few months later my neighbor across the street had roots in her lines! And i'm sure we do, too.
When a similar notice came for water lines a few months later - but not from the city, from the agency directly - my insurance agent did not think it was necessary (although not very expensive, either). So we skipped that one.