Hello I just want to know deeply difference mechanism of
converting between cryptocurrencies and selling or buying via order book. in exchanges like Binance
Is it possible to say both methods are the same when you want to trade ?

Thank you.
Yes they are same, only the interface os different, on some occasions you may not find the coin you want to convert so you have to convert into BTC or any coin which is available with the coin you trade then you need to repeat.
Swap trades are expensive when you compare with the traditional trade order book trading.