I doubt CASA would approve a Caravan on floats to do RPT in between Sydney and Canberra. I also doubt the aircraft would be approved for ASEPTA with floats on. How can the aircraft achieve the engine failure after take off turn back requirements with floats under it? I could understand them approving RPT up the coast to Newcastle if all the flying was done over water, however anything over land and particularly in between Sydney and Canberra doesn’t make sense. Winter would be interesting with freezing levels below lowest safes in an aircraft without boots, thought we stopped doing that kind of RPT stuff about 15 years ago.
I also doubt it was a proving flight with CASA onboard approving the operation to use a Twin Otter. A proving flight is normally done with the introduction of a new type and/or a new RPT route. Has the company actually got a Twin Otter on floats in Australia?