Data point is a single fact or piece of information. In the context of building management systems (BMS) data often is gathered with various types of sensors. In the data product context each sensor is a data point source (device in ontology).
Each device is not a data product. Data product contains payload which is a collection of data points. Of course there is possible situation that building includes just one CO2 measuring device and the data points of that device constitute data product payload.