Monitoring 121.5 doesn't make it a chat frequency. It's the best frequency to give an emergency call on anywhere in the world as high flying airline aircraft monitor the frequency .
You can't monitor the " control " frequency in other countries because control frequency boundaries are not shown on maps.
The frequency boundaries were removed from aussie maps with NAS but an outcry of ignorance resulted in the boundaries going back on the maps resulting in a non workable half wound back system that we now have.
That's why those incompetent people in CASA sent out the NOTAM stating that calls at non marked airports should be on the ATC area frequency. It's amateur hour with these CASA people.
And Flight Watch with VHF frequencies is not gone forever. Just wait and see!