Nydave wroteWhat do you put into a Bitcoin Atm and what comes out
You scan your private key (this is like your PIN number or password and is usually in the form of a QR barcode) into the Bitcoin ATM and this allows your Bitcoins to be transferred to the ATM. After it confirms the Bitcoins have been released to the ATM, it can then spit out the equivalent amount of local currency. [EDIT - Sorry about this, I was wrong. Apparently you send the Bitcoins you want to exchange for cash to an address the ATM gives you. You don't scan in your private key.]
To buy Bitcoins from a Bitcoin ATM you need to feed your local currency into the ATM and it will send the newly bought Bitcoins to your public key(sort of like the equivalent of an email address) that you also scan into the ATM.
This isn't a complete explanation of how Bitcoins work but it's basically correct.
As far as I know, the Bitcoin ATMs in Bali can only buy Bitcoins not sell them. They really shouldn't be called ATMs, it just confuses people.
Nydave wroteIf Bank Indonesia says its an invalid currency then why the need for Atm`s ,if you can`t spend it why would you need it,
Yep, that's a huge risk. Very few countries have banned it outright, and most developed countries are slowly working out how they'll classify and tax them.
Nydave wroteTheir goal of having 100 Atm`s worldwide,doesnt say much for its popularity,
I'm not sure what you're referring to here. But I'd agree that it's definitely not popular and it's definitely not ready for the mainstream and yet, even so, it's currently worth over USD$570.
My personal opinion is that it's going to take over the function that gold serves. It may catch on with retailers but I'm really not sure.