My Investigator player avoids using "Devise a Stratagem."

With the new rules of "Devise a Stratagem," it has actually discouraged my player from using it. If they want to attack a creature, and their roll for DaS is low, they can't attack that creature without a significant penalty. As such, they often just gorgo the roll and opt to just attack multiple times, and the surprising thing is it more often works out for them.

It literally works out for them more to NOT use their class' core ability.

Maybe it was just the scenario. They were fighting a bunch of creatures that used hit and run tactics in a narrow and winding cave system filled with water that created difficult terrain. As such, they would often only see one creature at a time, so that prevented the obvious solution of just attacking a different creature if the DaS roll is low.

But I'm just stumped. Like, what's the point of being that class if you don't use the stuff from that class?

EDIT: Dude, what's with the downvotes? I'm literally asking a question because I'm confused and looking for a solution.

EDIT 2: A couple people pointed out that this is a player perception problem; just a few chance rolls may have cemented a bit of gambler's fallacy. If so, how do I change that?

EDIT 3: Okay, I realize that the attack strategem is basically the same as it was before the remaster. Not my point here. My player is playing unoptimally and I was wondering if I could get SOLUTIONS.