1. India is under pressure from US and Russia to support their version. It's a catch 22 situation that can be only averted if India create something major in it's backyard and can then give excuse of been consumed by this event and has no time for the conflict in Europe (Ukraine - Russia).
That is ridiculous.
First of all, no one put great pressure on India. Did anyone threaten India with sanctions like Chinese is facing?
Modi or India gov is not chicken.
2. To check the detection and response capabilities of Pakistan's defence systems against their best weapon. They have successfully tested what achieved what they want.
That is missile not electronic warfare plane. It doesn't have the capability to inspect Pakistan side response. Those India's ground radars can't tell exactly what is happening on the other side. You need a plane in the sky to collect the signal.
3. To demonstrate capability of their supersonic missile. Already many south Asian countries have shown interest in acquiring it ...now India is hoping to get lot more attention and orders after this real-time demonstration.
It is really bad demonstration. Who wants a weapon can be easily mis-fired?
If it is a demonstration planned by India senior officer, then I have to question their IQ or yours. In any demonstration, the potential client will require details data and final picture. What you tell them: you need to contact customer service in Pakistan?
4. Setback to China on reliability of their weapon systems......many countries have given orders for HQ-9 air defence system...this incident will impact trust on Chinese weapons.
The first thing you need to prove is: there is HQ-9 deployed there.
And one tip: no one deploys their long range air-defense system so close to the border.
And I don't think Pakistan is so rich that they have air-defense system to cover every part of border.
5. Demotivate Pakistan (population), that their army despite claiming to track it since it took off, kept watching it helplessly and allowed it to travel 120 + KMs (3 minutes) inside it's territory and couldn't stop it.
Well, neither side is keeping that level of readiness. Basically, either side has that money to do it.
6. Signal Pakistan's establishment that Indian RSS govt. can now up the bar on such adventures after securing political supremacy and support of Indian mass population (as seen in recent elections). They can now pass any bill in both their parliament houses without opposition (being in majority in both the houses).
Modi is not that stupid and his life is not that boring.