Travelling around Thailand unvaccinated is a pain. Repeated covid tests, always running the risk of testing positive and off to hospitel/hospital together with a significant bill.
Doesn't finish for many people until they pass their final PCR before departure, depending on their airline and home country. An unexpected 10 days quarantine at the end of a 30 day holiday, on a 30 day visa, with work expecting you back, can cause all kinds of problems...
Don't forget to plan your return to Australia and beware of the consequences of testing positive before your return flight, a 10-day quarantine is required followed by a further 7 days in the country, before you can fly with Qantas etc...