Who still trades with discretion

Genuine question – if you have a real strategy let's say. Some kind of edge.

Say your Expected Value is positive. Congrats, you are in the top 1% of traders (the ones who don't lose money).

If your edge is based on your intuition, it isn't a real edge. Your emotions and vibes will change from day to day. Empirically, you don't even have a real edge – you are just getting lucky.

If your edge is based on actual rules, real market phenomena – then you can write those rules down. You can code up a backtest with those rules and see if the edge is real, or if you're getting lucky, or both.

So in either scenario, discretion is either a poor proxy for a rules-based system, or just luck disguised as trading acumen.