That’s usually the case.

I live and work on London time. If I want to have a phonecall with someone in the Philippines, I have to be mindful that 9am for me is 5pm for them, so I’ll need to make the effort to start early to catch them while they’re still at work.

Without timezones: If I want to have a phonecall with someone in the Philippines, I have to be mindful that their working day is 1am to 9am, so I’ll need to make the effort to start early to catch them while they’re still at work.

I’ll still need to lookup when their working day is, I’ll still have to adjust/account for it, and I’ll still have to get up early / start work early to make that call. Getting rid of timezones doesn’t get rid of that +8 or the affects of that +8, it just renames how we communicate it.

That 500AUD doesn’t just sit in an account and magically contribute to anything.

Currency exchange doesn’t actually happen in a vacuum. The only reason your Bangladeshi example is able to send 500AUD to his family, is that someone who has Bangladeshi Taka wants 500AUD to buy goods or services from somewhere that accepts AUD. And there’s a very short list of countries that spend AUD.

So that 500 doesn’t disappear to never return. That 500 is sold to someone who wants to use it to purchase australian exports.