Why the Mode Is Underrated
Because it sits in a corner of the interface, has no explanation attached, and looks like the sort of setting that adjusts difficulty in an ordinary game — where difficulty means how much skill is required. Here it means nothing of the kind. There is no skill component to adjust, so what the selector actually changes is the statistical shape of the round, and that is a much bigger deal than the placement suggests.
It is also the setting most likely to be changed impulsively. Nobody switches their stake by a factor of ten in the middle of a losing run, but plenty of players jump from easy to hardcore, which is a comparable change in exposure.
One Thing Worth Doing
Open the lane table for each mode once and read the whole column. Seeing 24 gentle steps beside 15 aggressive ones makes the trade concrete in a way that no description manages, and it usually settles which mode suits you for good.
How a single round works on any of them is set out on the round explainer, and the rest of the guides are listed on the home page.