>>281418382
Because depending on the point of view, money can also be power. Getting rid of what you don't need (can't use), buying something for the same price yet essentially of greater value means a lot in the long run. If I find a rare mineral I may not know how to wield it, but someone with a talented eye and connections to those things could find someone that would pay big money for that. Furthermore, value changes according to the location, a diamond could be just a shiny pebble for someone dying of thirst in the desert willing to trade everything he owns for a jar of water.
We all joke about how the nobility is retarded in isekai and should fall sooner or later, but reality is in real life this happened a ton of times. Worker plebeians could become farmers and from farmers there would be born merchants. Rich that rival high nobles, yet the lack of the titles themselves. In turn, falling houses would marry their daughters to merchants for the shared fortune, granting them the title they longed for and thus the bloodline would continue. Even if not by the family that got the fortune, that merchant would now carry their name and therefore the house would be restored.
>Is funding dictators and bandits the only way to combat them?
Not necessarily. Direct attack or assassination maybe, but some merchants can thrive in conflict. They are the true winners of wars after all.
Notice how companies can declare poverty and rebrand themselves. Some of those juggernauts could lose all their money at once and they'd still find a way to recover with the structures and resources they own anyway.