This is where it gets more interesting.
Rule based is where you have a rule for everything; this is more apparent for algos—but for anyone religiously sticking to a trade plan this applies too.
The main strength here is you will avoid your emotions clouding your judgement. However, the con is you may not adapt to market conditions.
Whereas with discretionary trading, as the name applies allows you to trade with your discretion. You will have to be on the ball and continually research and stay “plugged in”; unlike being rule based you will not have free time because you need to know EVERYTHING if you’re going to be doing things at your discretion.
You will ebb and flow with the market.
You can react fast when the market changes as you effectively make the rules, but you can also easily trick yourself into making reckless choices about risk management and trade based on emotion which leads to losses.
A good trade plan rather would find a way to factor both in.