I have a bachelors in applied mathematics so I've passed higher level math courses but I never used any of it. The higher up you go, the more specialized the concepts. Concepts are applied like tools. Analogizing, how often does a person really need a jigsaw? On the other hand, how often does a person need a basic saw? How often does a person need a diamond drill bit? How often does a person need a basic drill?

My students became absolute badasses at lower level math as a result of this. Lower level math is the low hanging fruit that yields profits more often than anything else in math. Knowing half a dozen different algorithms for executing a multiplication or subtraction problem is like having half a dozen different screwdrivers, each with their own head. If you select the right tool for each specific job, the job is accomplished quickly, easily, efficiently, etc.

Not only is having mental math skill directly useful for calculating things, it is impressive to those who have not developed this skillset. Some non-zero number of people who have not developed this skillset are in positions of power and influence. Luck is the intersection of preparation and opportunity. Impressing a person like that is how quantum leaps are made in careers, so mastery of low level math can change a person's entire life trajectory.

Capable people on benefit are injustice. They learn that they can live doing nothing and are teaching all the others that putting efforts in life is worthless. They make being a productive person a stupid choice.