where is the bitcoin mostly used after speculation on the markets?
Speculations in the market get Bitcoin into two phase [1] attempt from the whales to get coins from the weak-hands for their gains and [2] getting their stash pass on-to newborn investors for gains. The two are all speculations among inhabitant of this technology and it's a tool
for loss/gain purposes.what is the area of economics that dont work without bitcoin ?
With my elementary knowledge in economics, the principles that work with Bitcoin are those that equally work for our real-world[fiats]. So, no area of economics that don't work with Bitcoin, except the principles of total supply which doesn't work with fiats IMO.