I've been confused for a while on what happens to a particular cryptocurrency when swapped to another. I mean when a swap may be BNB to get usdt, what happens to the BNB?
The simplest but most confusing question, we all newbies have faced, the simplest answer is don't look at the one side of the picture, this means if someone is swapping BNB for USDT then look at the other side of the picture which is there is another person who wishes to swap his USDT for the BNB. But now you will think what if there is no other person at the time of swapping of BNB looking for USDT? Then your BNB will be swapped from the pool of the platform, pools are made for seamless trading without any stop. I hope you understand. If not then don't hesitate to ask again.
Another confusion I have is about BTC.
BTC has a total supply of 19,495,156 million. Now the entire 19,495,156 are in circulation which means they are being held by holders/users. But another user can always swap another coin to BTC at anytime and receive the BTC, so where is the BTC coming from since it already in circulation (held by other holders)?
BTCs don't have a supply of 19,495,156 million in total, because the total supply is round off to 21 million. The supply you have mentioned is the one which is mined till now and is already in circulation. And the answer to your query is almost the same as the first one.
As if one is selling the BTC then there is another person at the other end buying it too or vice versa. And if there is no other entity then the funds will be provided from the pools of the exchange or swap you are using to swap sell or buy the BTC. Let's say you wanted to sell the BTC and wanted to buy USDT in exchange and you have selected the BTC/USDT pair and once you hit the sell button you will quickly get usdt when your selling price will hit.
And the USDT will be given to you from the pools of USDT money. And that gap will be covered later once a person looking to sell USDT in exchange of BTC.