Well, Heimdall is a great app. Anything you can do with Homey is better than nothing. But it will never get any kind of certification that an insurance company would accept. If isn’t designed for/built with the proper failsafes that real security systems have.
You can of course link actual smart alarm systems with Homey, that is another matter, but Homey shouldn’t be crucial to the alarm functionality if you want it to be insurance-grade.