If the lose isn't going to dramatically impact your financial wellbeing then insurance is always an irrational bet.
Getting a contents policy in a safe neighborhood where you know that there's little risk is likely not a good deal. Getting a contents policy when you've learned that your neighbors are getting into hard drugs is probably a good deal.
Paying $19/mo for third-party full coverage + theft on your $1,000 mobile phone is probably not a good deal even if you know you are high risk, for the simple reason that at $19, they game must be that they will find any reason to refuse to pay, and will give you a poorly refurbished phone for your troubles if you make them honor the insurance.