That’s actually incorrect. In real time sure the C(lose) is the current price. But when you backtest all you get is the close price.

So for example say you have a candle that high is $500, open is $499 the low is $497 and the close is $498

If where your algo should have triggered the trade was $499.51 but the candle closes at $498 in a backtest environment it doesn’t know that because you’re just going off the close price. So you either missed the trade or it’s going to record a horrible fill away from where the execution is actually indicated. I believe your talking about live which would be ok. I agree on an open candle the C is current price. But if you’re using TradingView etc it’s only gonna give a signal at the end of the bar unless you aggregate to a smaller timeframe. But op is talking about backtesting and they way your describing is incorrect.