Where in world are people actually using BTC for purchase vs rest of us who invest and trade.
It actually depend on what a person wants to do with his/her bitcoin, its a case to case basis, a few days ago i saw a video on youtube that a man bought a lamborghini aventador via bitcoin.
While in other parts of the world bitcoin is being used to pay bills such as electricity and water bills, while some just want to buy a coffee or other things they can with bitcoin.
On some special occasions, there some people who trade bitcoin for real cash by passing exchanges for the sole purpose of being anonymous.
where else in world is it being used as a currency?
I think most part of the develop countries, citizen there use bitcoin to purchase anything they want in exchange for bitcoin, but i think bitcoin is hardly used by people nowadays to buy stuff offline, mainly the reason for this is that the fees that you will have to pay in extra just to make a transaction which is not good right now.