and they said that it does not have the open orders feature like most crypto exchanges have.
What do you mean by "open orders" feature. If you mean that you can buy and hold indefinitelly, you are right. With margin trading, you buy contracts that either expire after some time, or you have to pay founding fees.
Just like the crypto exchanges, we also invest and trade an amount that we could afford losing.
The only differenence is that you can trade with more money than what you actually have. All the other aspects are more or less the same. But you don't have to borrow. Nobody is forcing you to do so.
If you are used to trading on binance, most marging trading platforms allow you to go Short in additon to what you would usualy do on Binance, which is go long. This is a huge benefit over most of the "normal" exchanges.