I think a smart thermostat is a must have without Alexa, mine is from Nest. Also have some Wemo switches and plugs along with Hue lighting. I also have some Fire TV devices, that is still not compatible with Blink live view. I don’t consider the mattress a must have device to use with Alexa. If I were buying a camera based on Alexa compatibility and “home automation” in general, Blink as of today would not be the camera I choose. Hue, Nest, and Wemo integrate with a wider range of other platforms and can easily create automations either natively or with an app without the use of a smart hub. I don’t consider a smart hub a must have to use with Alexa, unless you have a mix of devices or ecosystems that need to be automated using a single platform. Depending on the devices purchased and use case a smart hub would not be needed. Although a smart hub would provide more logical automations with more conditions.