The targeted court cases are to argue that the previously passed legislation already covers these particular facts.

If the legislature passes a law that says “making false statements to another in order to obtain something of value is fraud,” you can expect litigation about the actual contours of what is or isn’t fraud.

Same with legislation against driving at an unsafe speed, causing a nuisance to your neighbors, discriminating against employees on the basis of sex, etc. Court cases decide the edge cases.

If the legislature passes a law banning gambling outside of licensed institutions, and banning gambling for minors, you can expect litigation about what actually is or isn’t gambling.