The approaches are entirely different :
I will like to tell with an example.
Suppose in Leo ascendent : Mars lord of 4,10H in 9H..
Traditionally we will deduce two different results :
1) 4L in 9H, [for eg Mother has more influences on 9H matters, we have lot of classic text for it]
2)10L in 9H [Karma is more influenced by Dharma]
Here results are dependent to each other houses and there is some relationship status. Hence emotional and sensitivity, effects on 'Mann'\ Mind is better defined.
Now suppose query related to career one will predict that it will be family related business or Raj yoga fructifying. Here emotional status is more profound.
Now In KP suppose Sun Signify Mars that we will say Sun's significance is 4,10 and 9H : Here we are taking the permutation and combination of 4,10,9 house independently. Here results of each houses are of more profound. We say one can expect result related to Mother, Father and work.
Now suppose query is to find career than one can predict that career is related to matters signified 4,10,9 houses. In this system one can deduce Matters (non living objects) more clearly related to houses but attachment cannot be assessed easily.
Both is important.
Whatever i have discussed above is by considering only one aspect of each system. But by applying other aspect of each system we can get the whole picture by each system system itself.
I hope i am able to convey my thoughts.
Vedic Astrologer and Vastukar