This second reference may be confusing because it is under the Cloud-Connected Integrations section, but this is something that has been discussed and it keeps being reviewed (making the documentation of profile categories agnostic between device integrations).
You will find categories mentioned in Interaction Types | SmartThings Developers which means those who were involved with Schema integrations may be familiar with them. However they seem to be appearing in lots of other places and I don’t think ST realise that the punters don’t really have a scooby what they are beyond being able to make a reasonable guess.