My question is: how efficient are these AIs really? Do they significantly improve a trader's overall profit and loss ratio, or is the improvement only marginal?
These AIs are just guides. If they are making enough money through the trader's way of trading, it's because they're there only to help but not they are the one that's entirely making the trades. Because if AIs are there to trade, then we won't be doing any trades anymore and let them work for our money and so we won't be bothered anymore of how to decide to make our trades win. But no, AIs/bots have been there already even the trend of AI came. It's not the actual AI doing the trade for us because many misconception are still thinking like that.
You are right there. AI trading assistants are just there to lead and guide us, but won’t decide the future of our trades. It’s still our own personal capabilities and skills that will determine the future of our trades, so even if you use AI but you have not completely understood the nature of trading and how to maximize its trading potentials, then you will never achieve your target goal in trading.
Know that trading is all about mental, emotional and even financial decision, so if you think you fail to prepare them prior to trading, expect that you will still experience consistent mistakes and losses before you will gain mastery and profitability on your trades. AI is an outline, but you should be the one navigating your trades.