Cryptocurrency trading pairs for example ltc/btc, doge/btc should be paired using some criteria. I'd like to comprehend on what basis they are paired.
Exchanges generally choose a few base currencies and build trading pairs on top of them. It has multiple reasons:
- The exchange needs to find a base currency where people can understand the value of X from X/base. BTC/USD is $1350 that gives you a clear idea of how much BTC is worth in USD. That is different from LTC/DRK = 0.98. What did that tell you? Not much. You are in need of a base currency you are familiar with. Most people have a good feeling for the value of USD. Therefore, it is a good denominator.
- The exchange needs to find a base currency which people are most likely to deposit/withdraw for trading. After you are done with trading numerous altcoins with each other, you want to exit the trading platform in a currency that has a meaning to you. To make that easy, base pairs are usually BTC.
- This is probably the most important, if an exchange has BTC LTC USD, they will most likely not create BTC/LTC pair because that will decrease the liquidity of LTC/USD pair. They will most likely only offer BTC/USD and LTC/USD. On top of that, the extra pair will have maintenance cost to the exchange.