There are literally people who use order book to make money, so it is not the same for a high level trader for sure, but when it comes down to making a trade, like your whole purpose is to turn bitcoin into bnb? Then they are the same thing and there is absolutely no difference at all.

One difference is, if you are talking about just a very low level coin, the value may drop, if there is not enough coin in the order book and you do a market trade (the converting) then the system will just sell it all on orderbook anyway but since it doesn't have many buyers the result will be substandard and you will lose out on some profit. That's about it though, as long as you deal with top level coins (and binance usually just have that) and you are doing something small, then it is the same thing when you just want to turn one thing into another.