The success of Google's new Nest Hub smart device will likely depend on whether people trust Google enough to let the company monitor them whilst they are asleep.

Many reviewers praise the product's basic functions, usability, and sleep monitoring capabilities. But some commentators questioned the accuracy of Google's sleep sensing and analytics. Others highlight Google's rapacious quest for user data, and wonder what the company might do with it - now, and in the future. 

Optional for now, it appears Google is looking to charge for the service going forward. The company says none of the data collected through Nest Hub's sleep sensing feature will be used to sell personalised advertising.