The ports on the hubs are NOT grease injectors, they are meant to be used by pro team mechanics to inject OIL into the hubs, when being used for time trials. Using oil rather than grease is a very old trick used to to lower friction and reduce time. On older models, the ports on the cassette housing can be used to inject grease into the sealed bearings that are mounted on the outside of the housing, this is probably still true for the new models as well.

It is a good idea to use a light lubricant on the derailleur and brake pivots, brake lever pivots, derailleur pulleys and on the end of the brake springs, (I use silicon myself as it does not attract dirt )