In CL en CC the runner up also gets a price. It would be fair if the runner up in the national cup also gets a runner up price. It is one the only possibility a lower league team could 'win' something. 

For example. I now reached the cup final two years in a row (first time as C-division team and second time as B-division team) and lost the final to the national champion and the runner up of the A-division. Both times my team didn't get anything for reaching the final.

Winning each stage grants the corresponding bonus in gold... Both times u get reward for break semi-final. But that's not what you want. You want a runner up prize. Maybe there is no runner up prize in the national cup because it is not that important? C.C and C.L is way more important and hard.

Even so...it should be the same just like CL and CC

no need even in CL/CC
there are rewards on lower grades