I use All to explore.

I start with subscribed, until everything on my feed starts to look familiar. Then switch to Local, which works well to find new communities because my instance is somewhat topical. And then if I run out of content, I move on to All to see what else is out there.

I’m not really scrolling All for content, I’m more on the lookout for interesting communities.

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.