I think that the concept behind Circle is great. The problem is that there is not nearly enough information on the insurance (how it is going to work, who their provider is, etc.). It's leading a lot of us to believe that the insurance idea is unsustainable. Until we get more information on that, it's hard to make an accurate judgement.
Insurance really shouldn't be considered as much of a benefit either because:
https://www.circle.com/user-agreement"If your bitcoins are lost or stolen as a result of your own failure to maintain proper security protocols in accordance with Section 1.3, such loss is not be covered by Circle’s insurance."
This is equally applicable to Xapo and Elliptic Vault who offer insurance. Basically, what this insurance covers is third party oversight to insure security of others and/or owners stealing funds. This is important but you are just as at risk from theft if you stored your bitcoins yourself.
Additionally, we don't want to encourage people to become comfortable with hot wallets as they will open themselves up to other forms of theft like unjustified taxes and privacy invasion.
Bitcoin is meant to be Peer to Peer; lets keep it clean!