(i) Provide our sarkari scientists a phot-op to pose in rambo like combat gear (ii) Create a huge media cry all the way from from Washington to Sydney. (iii) Provide an opportunity to Pakistan to exceed India's total
In the end we are back to square one. I think instead of wasting money and putting up a stupid show India needs to focus on real issues such as infrastructure, poverty and corruption.
Besides having nukes these days is not that big of a deal. A lot of things can be simulated in the lab and one rarely needs full scale/blown tests.