This is a difficult question to answer because it involves an inter-disciplinary approach, and thus knowledge of several domains.
As another poster mentions, IoT devices haven't historically been very secure. The dangers of turning the thing on/off multiple times a minute is going to vary greatly with the design of the specific product. Unless someone does actual testing or has specific knowledge of the device, even the folks over at electronics are unlikely to give you a good answer if the thing is dangerous or not. Any consumer electronic device is going to be rated for "typical usage", not doing something strange like turning it on/off every two seconds for 12 hours.
Personally I'd be more concerned about the thing turning into a piece of trash in 3-5 years. Any device that relies on outside infra-structure to work means that you're suddenly completely dependent on it. If the cloud provider goes out of business, drops support for version X, you could very quickly have an expensive paperweight.