Hmmm because NISM certificates 'Enlighten' you? Make you a good trader and a better human being? Your guess is as good as mine! :-) ... if NSE says it's required, who am I to complain.
Exchanges in India are very restrictive when it comes to allowing retail traders to automate. The reason for this is, when trades are automated a small change in the strategy could lead to losing a lot of money.
So exchanges allow only professional traders to automate, and this as per exchange rules require the trader to be registered as an authorized person on the exchange and also have access to dealer terminals. To get this dealer terminal, the person will also need to clear the NISM dealers certification, this exam in a way ensures that the trader has minimum knowledge required and understands the risks of automating trades.