IF YOU ARE GOING TO FLY CLEAR OF CLOUD IN CLASS G AIRSPACE IT IS A LEGAL REQUIREMENT THAT YOU HAVE A VHF RADIO AND BROADCAST THAT THIS IS HOW YOU ARE OPERATING.
Nobody reads the full regulation!
If an IFR flight is descending in your area or another aircraft is doing the same thing around the other side of the cloud they have to know you are there. The 1500' and 1000m is there to provide adequete reaction time in the event of a sudden appearance of another aircraft.
Eg. On the centre frequency "All Stations Maleny, 172 ABC is tracking north over the navaid at 2800' OPERATING CLEAR OF CLOUD, Maleny"
That way anyone on frequency knows and Centre can also advise any IFR traffic in the area as well.
The requirement to remain in sight of ground or water applies to visual navigation below 2000' and is not specific to operating clear of cloud.