People can include allowances in their consideration or not, I don’t care, however to suggest they are solely to be spent in port is a bit misleading. Under the new allowance system in QF LH you earn the allowance as soon as you sign on at your home base, until you return days later. So a 24 hour slip, SIN return will earn you close to $800 AUD tax free. You can have plenty of beers and ‘nuclear chicken’ and you won’t spend half of that.
I wouldn’t base my career plans around it but it’s a nice earner and can’t be ignored.