Chopped tomato-onion-ginger-garlic into paste vs sliced tomato-onion-ginger-garlic when making curry base for indian dish
The main issue I see with making a paste out of the ingredients is not being able to caramelize the onion.

Onion caramelizes at around 230 degrees Fahrenheit. When you make your ingredients into a paste, you will not be able to achieve a temperature this high in your mixture without drastically reducing the water content in your mixture.

To get around this, first caramelize your onion then add it to the other ingredients to make a paste. 

The main difference of making the paste is having a homogeneous taste throughout your base. It'll taste exactly the same as you eat it. If you chop it will taste slightly different based on the different ratio of onion, ginger, and garlic bits you have on that bite. Both can be good depending on your taste preference.