Currency Converter Calculator

Day 4 Challenge: Design a calculator.
It started out as a converter & calculator, but as I began to think its function and UX, I found that combine a Currency Converter with a Calculator is not a good idea, which makes both function an imperfect experience.
So I hide the calculation part, and concentrated on the converter part.
I searched the usage of separators in numbers and found that they are used differently in different regions. There were some tips that mention the possibility of using spaces to avoid misunderstandings and I tried.
Also I added the '000' button for quickly adding big number since the price of BTC is sooo high lol. And I added color to distinguish the output part from the input part.
(Well, just some irresponsible ideas that need to be tested in formal design to ensure usability :)